3a38a9680cdba53c1d78c922e861cf4ec74de4af
[openocd.git] / doc / openocd.texi
1 \input texinfo @c -*-texinfo-*-
2 @c %**start of header
3 @setfilename openocd.info
4 @settitle OpenOCD User's Guide
5 @dircategory Development
6 @direntry
7 * OpenOCD: (openocd). OpenOCD User's Guide
8 @end direntry
9 @paragraphindent 0
10 @c %**end of header
11
12 @include version.texi
13
14 @copying
15
16 This User's Guide documents
17 release @value{VERSION},
18 dated @value{UPDATED},
19 of the Open On-Chip Debugger (OpenOCD).
20
21 @itemize @bullet
22 @item Copyright @copyright{} 2008 The OpenOCD Project
23 @item Copyright @copyright{} 2007-2008 Spencer Oliver @email{spen@@spen-soft.co.uk}
24 @item Copyright @copyright{} 2008-2010 Oyvind Harboe @email{oyvind.harboe@@zylin.com}
25 @item Copyright @copyright{} 2008 Duane Ellis @email{openocd@@duaneellis.com}
26 @item Copyright @copyright{} 2009-2010 David Brownell
27 @end itemize
28
29 @quotation
30 Permission is granted to copy, distribute and/or modify this document
31 under the terms of the GNU Free Documentation License, Version 1.2 or
32 any later version published by the Free Software Foundation; with no
33 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
34 Texts. A copy of the license is included in the section entitled ``GNU
35 Free Documentation License''.
36 @end quotation
37 @end copying
38
39 @titlepage
40 @titlefont{@emph{Open On-Chip Debugger:}}
41 @sp 1
42 @title OpenOCD User's Guide
43 @subtitle for release @value{VERSION}
44 @subtitle @value{UPDATED}
45
46 @page
47 @vskip 0pt plus 1filll
48 @insertcopying
49 @end titlepage
50
51 @summarycontents
52 @contents
53
54 @ifnottex
55 @node Top
56 @top OpenOCD User's Guide
57
58 @insertcopying
59 @end ifnottex
60
61 @menu
62 * About:: About OpenOCD
63 * Developers:: OpenOCD Developer Resources
64 * Debug Adapter Hardware:: Debug Adapter Hardware
65 * About Jim-Tcl:: About Jim-Tcl
66 * Running:: Running OpenOCD
67 * OpenOCD Project Setup:: OpenOCD Project Setup
68 * Config File Guidelines:: Config File Guidelines
69 * Server Configuration:: Server Configuration
70 * Debug Adapter Configuration:: Debug Adapter Configuration
71 * Reset Configuration:: Reset Configuration
72 * TAP Declaration:: TAP Declaration
73 * CPU Configuration:: CPU Configuration
74 * Flash Commands:: Flash Commands
75 * Flash Programming:: Flash Programming
76 * PLD/FPGA Commands:: PLD/FPGA Commands
77 * General Commands:: General Commands
78 * Architecture and Core Commands:: Architecture and Core Commands
79 * JTAG Commands:: JTAG Commands
80 * Boundary Scan Commands:: Boundary Scan Commands
81 * Utility Commands:: Utility Commands
82 * TFTP:: TFTP
83 * GDB and OpenOCD:: Using GDB and OpenOCD
84 * Tcl Scripting API:: Tcl Scripting API
85 * FAQ:: Frequently Asked Questions
86 * Tcl Crash Course:: Tcl Crash Course
87 * License:: GNU Free Documentation License
88
89 @comment DO NOT use the plain word ``Index'', reason: CYGWIN filename
90 @comment case issue with ``Index.html'' and ``index.html''
91 @comment Occurs when creating ``--html --no-split'' output
92 @comment This fix is based on: http://sourceware.org/ml/binutils/2006-05/msg00215.html
93 * OpenOCD Concept Index:: Concept Index
94 * Command and Driver Index:: Command and Driver Index
95 @end menu
96
97 @node About
98 @unnumbered About
99 @cindex about
100
101 OpenOCD was created by Dominic Rath as part of a 2005 diploma thesis written
102 at the University of Applied Sciences Augsburg (@uref{http://www.hs-augsburg.de}).
103 Since that time, the project has grown into an active open-source project,
104 supported by a diverse community of software and hardware developers from
105 around the world.
106
107 @section What is OpenOCD?
108 @cindex TAP
109 @cindex JTAG
110
111 The Open On-Chip Debugger (OpenOCD) aims to provide debugging,
112 in-system programming and boundary-scan testing for embedded target
113 devices.
114
115 It does so with the assistance of a @dfn{debug adapter}, which is
116 a small hardware module which helps provide the right kind of
117 electrical signaling to the target being debugged. These are
118 required since the debug host (on which OpenOCD runs) won't
119 usually have native support for such signaling, or the connector
120 needed to hook up to the target.
121
122 Such debug adapters support one or more @dfn{transport} protocols,
123 each of which involves different electrical signaling (and uses
124 different messaging protocols on top of that signaling). There
125 are many types of debug adapter, and little uniformity in what
126 they are called. (There are also product naming differences.)
127
128 These adapters are sometimes packaged as discrete dongles, which
129 may generically be called @dfn{hardware interface dongles}.
130 Some development boards also integrate them directly, which may
131 let the development board connect directly to the debug
132 host over USB (and sometimes also to power it over USB).
133
134 For example, a @dfn{JTAG Adapter} supports JTAG
135 signaling, and is used to communicate
136 with JTAG (IEEE 1149.1) compliant TAPs on your target board.
137 A @dfn{TAP} is a ``Test Access Port'', a module which processes
138 special instructions and data. TAPs are daisy-chained within and
139 between chips and boards. JTAG supports debugging and boundary
140 scan operations.
141
142 There are also @dfn{SWD Adapters} that support Serial Wire Debug (SWD)
143 signaling to communicate with some newer ARM cores, as well as debug
144 adapters which support both JTAG and SWD transports. SWD supports only
145 debugging, whereas JTAG also supports boundary scan operations.
146
147 For some chips, there are also @dfn{Programming Adapters} supporting
148 special transports used only to write code to flash memory, without
149 support for on-chip debugging or boundary scan.
150 (At this writing, OpenOCD does not support such non-debug adapters.)
151
152
153 @b{Dongles:} OpenOCD currently supports many types of hardware dongles:
154 USB-based, parallel port-based, and other standalone boxes that run
155 OpenOCD internally. @xref{Debug Adapter Hardware}.
156
157 @b{GDB Debug:} It allows ARM7 (ARM7TDMI and ARM720t), ARM9 (ARM920T,
158 ARM922T, ARM926EJ--S, ARM966E--S), XScale (PXA25x, IXP42x), Cortex-M3
159 (Stellaris LM3, ST STM32 and Energy Micro EFM32) and Intel Quark (x10xx)
160 based cores to be debugged via the GDB protocol.
161
162 @b{Flash Programming:} Flash writing is supported for external
163 CFI-compatible NOR flashes (Intel and AMD/Spansion command set) and several
164 internal flashes (LPC1700, LPC1800, LPC2000, LPC4300, AT91SAM7, AT91SAM3U,
165 STR7x, STR9x, LM3, STM32x and EFM32). Preliminary support for various NAND flash
166 controllers (LPC3180, Orion, S3C24xx, more) is included.
167
168 @section OpenOCD Web Site
169
170 The OpenOCD web site provides the latest public news from the community:
171
172 @uref{http://openocd.org/}
173
174 @section Latest User's Guide:
175
176 The user's guide you are now reading may not be the latest one
177 available. A version for more recent code may be available.
178 Its HTML form is published regularly at:
179
180 @uref{http://openocd.org/doc/html/index.html}
181
182 PDF form is likewise published at:
183
184 @uref{http://openocd.org/doc/pdf/openocd.pdf}
185
186 @section OpenOCD User's Forum
187
188 There is an OpenOCD forum (phpBB) hosted by SparkFun,
189 which might be helpful to you. Note that if you want
190 anything to come to the attention of developers, you
191 should post it to the OpenOCD Developer Mailing List
192 instead of this forum.
193
194 @uref{http://forum.sparkfun.com/viewforum.php?f=18}
195
196 @section OpenOCD User's Mailing List
197
198 The OpenOCD User Mailing List provides the primary means of
199 communication between users:
200
201 @uref{https://lists.sourceforge.net/mailman/listinfo/openocd-user}
202
203 @section OpenOCD IRC
204
205 Support can also be found on irc:
206 @uref{irc://irc.freenode.net/openocd}
207
208 @node Developers
209 @chapter OpenOCD Developer Resources
210 @cindex developers
211
212 If you are interested in improving the state of OpenOCD's debugging and
213 testing support, new contributions will be welcome. Motivated developers
214 can produce new target, flash or interface drivers, improve the
215 documentation, as well as more conventional bug fixes and enhancements.
216
217 The resources in this chapter are available for developers wishing to explore
218 or expand the OpenOCD source code.
219
220 @section OpenOCD Git Repository
221
222 During the 0.3.x release cycle, OpenOCD switched from Subversion to
223 a Git repository hosted at SourceForge. The repository URL is:
224
225 @uref{git://git.code.sf.net/p/openocd/code}
226
227 or via http
228
229 @uref{http://git.code.sf.net/p/openocd/code}
230
231 You may prefer to use a mirror and the HTTP protocol:
232
233 @uref{http://repo.or.cz/r/openocd.git}
234
235 With standard Git tools, use @command{git clone} to initialize
236 a local repository, and @command{git pull} to update it.
237 There are also gitweb pages letting you browse the repository
238 with a web browser, or download arbitrary snapshots without
239 needing a Git client:
240
241 @uref{http://repo.or.cz/w/openocd.git}
242
243 The @file{README} file contains the instructions for building the project
244 from the repository or a snapshot.
245
246 Developers that want to contribute patches to the OpenOCD system are
247 @b{strongly} encouraged to work against mainline.
248 Patches created against older versions may require additional
249 work from their submitter in order to be updated for newer releases.
250
251 @section Doxygen Developer Manual
252
253 During the 0.2.x release cycle, the OpenOCD project began
254 providing a Doxygen reference manual. This document contains more
255 technical information about the software internals, development
256 processes, and similar documentation:
257
258 @uref{http://openocd.org/doc/doxygen/html/index.html}
259
260 This document is a work-in-progress, but contributions would be welcome
261 to fill in the gaps. All of the source files are provided in-tree,
262 listed in the Doxyfile configuration at the top of the source tree.
263
264 @section Gerrit Review System
265
266 All changes in the OpenOCD Git repository go through the web-based Gerrit
267 Code Review System:
268
269 @uref{http://openocd.zylin.com/}
270
271 After a one-time registration and repository setup, anyone can push commits
272 from their local Git repository directly into Gerrit.
273 All users and developers are encouraged to review, test, discuss and vote
274 for changes in Gerrit. The feedback provides the basis for a maintainer to
275 eventually submit the change to the main Git repository.
276
277 The @file{HACKING} file, also available as the Patch Guide in the Doxygen
278 Developer Manual, contains basic information about how to connect a
279 repository to Gerrit, prepare and push patches. Patch authors are expected to
280 maintain their changes while they're in Gerrit, respond to feedback and if
281 necessary rework and push improved versions of the change.
282
283 @section OpenOCD Developer Mailing List
284
285 The OpenOCD Developer Mailing List provides the primary means of
286 communication between developers:
287
288 @uref{https://lists.sourceforge.net/mailman/listinfo/openocd-devel}
289
290 @section OpenOCD Bug Tracker
291
292 The OpenOCD Bug Tracker is hosted on SourceForge:
293
294 @uref{http://bugs.openocd.org/}
295
296
297 @node Debug Adapter Hardware
298 @chapter Debug Adapter Hardware
299 @cindex dongles
300 @cindex FTDI
301 @cindex wiggler
302 @cindex zy1000
303 @cindex printer port
304 @cindex USB Adapter
305 @cindex RTCK
306
307 Defined: @b{dongle}: A small device that plugs into a computer and serves as
308 an adapter .... [snip]
309
310 In the OpenOCD case, this generally refers to @b{a small adapter} that
311 attaches to your computer via USB or the parallel port. One
312 exception is the Ultimate Solutions ZY1000, packaged as a small box you
313 attach via an ethernet cable. The ZY1000 has the advantage that it does not
314 require any drivers to be installed on the developer PC. It also has
315 a built in web interface. It supports RTCK/RCLK or adaptive clocking
316 and has a built-in relay to power cycle targets remotely.
317
318
319 @section Choosing a Dongle
320
321 There are several things you should keep in mind when choosing a dongle.
322
323 @enumerate
324 @item @b{Transport} Does it support the kind of communication that you need?
325 OpenOCD focusses mostly on JTAG. Your version may also support
326 other ways to communicate with target devices.
327 @item @b{Voltage} What voltage is your target - 1.8, 2.8, 3.3, or 5V?
328 Does your dongle support it? You might need a level converter.
329 @item @b{Pinout} What pinout does your target board use?
330 Does your dongle support it? You may be able to use jumper
331 wires, or an "octopus" connector, to convert pinouts.
332 @item @b{Connection} Does your computer have the USB, parallel, or
333 Ethernet port needed?
334 @item @b{RTCK} Do you expect to use it with ARM chips and boards with
335 RTCK support (also known as ``adaptive clocking'')?
336 @end enumerate
337
338 @section Stand-alone JTAG Probe
339
340 The ZY1000 from Ultimate Solutions is technically not a dongle but a
341 stand-alone JTAG probe that, unlike most dongles, doesn't require any drivers
342 running on the developer's host computer.
343 Once installed on a network using DHCP or a static IP assignment, users can
344 access the ZY1000 probe locally or remotely from any host with access to the
345 IP address assigned to the probe.
346 The ZY1000 provides an intuitive web interface with direct access to the
347 OpenOCD debugger.
348 Users may also run a GDBSERVER directly on the ZY1000 to take full advantage
349 of GCC & GDB to debug any distribution of embedded Linux or NetBSD running on
350 the target.
351 The ZY1000 supports RTCK & RCLK or adaptive clocking and has a built-in relay
352 to power cycle the target remotely.
353
354 For more information, visit:
355
356 @b{ZY1000} See: @url{http://www.ultsol.com/index.php/component/content/article/8/210-zylin-zy1000-main}
357
358 @section USB FT2232 Based
359
360 There are many USB JTAG dongles on the market, many of them based
361 on a chip from ``Future Technology Devices International'' (FTDI)
362 known as the FTDI FT2232; this is a USB full speed (12 Mbps) chip.
363 See: @url{http://www.ftdichip.com} for more information.
364 In summer 2009, USB high speed (480 Mbps) versions of these FTDI
365 chips started to become available in JTAG adapters. Around 2012, a new
366 variant appeared - FT232H - this is a single-channel version of FT2232H.
367 (Adapters using those high speed FT2232H or FT232H chips may support adaptive
368 clocking.)
369
370 The FT2232 chips are flexible enough to support some other
371 transport options, such as SWD or the SPI variants used to
372 program some chips. They have two communications channels,
373 and one can be used for a UART adapter at the same time the
374 other one is used to provide a debug adapter.
375
376 Also, some development boards integrate an FT2232 chip to serve as
377 a built-in low-cost debug adapter and USB-to-serial solution.
378
379 @itemize @bullet
380 @item @b{usbjtag}
381 @* Link @url{http://elk.informatik.fh-augsburg.de/hhweb/doc/openocd/usbjtag/usbjtag.html}
382 @item @b{jtagkey}
383 @* See: @url{http://www.amontec.com/jtagkey.shtml}
384 @item @b{jtagkey2}
385 @* See: @url{http://www.amontec.com/jtagkey2.shtml}
386 @item @b{oocdlink}
387 @* See: @url{http://www.oocdlink.com} By Joern Kaipf
388 @item @b{signalyzer}
389 @* See: @url{http://www.signalyzer.com}
390 @item @b{Stellaris Eval Boards}
391 @* See: @url{http://www.ti.com} - The Stellaris eval boards
392 bundle FT2232-based JTAG and SWD support, which can be used to debug
393 the Stellaris chips. Using separate JTAG adapters is optional.
394 These boards can also be used in a "pass through" mode as JTAG adapters
395 to other target boards, disabling the Stellaris chip.
396 @item @b{TI/Luminary ICDI}
397 @* See: @url{http://www.ti.com} - TI/Luminary In-Circuit Debug
398 Interface (ICDI) Boards are included in Stellaris LM3S9B9x
399 Evaluation Kits. Like the non-detachable FT2232 support on the other
400 Stellaris eval boards, they can be used to debug other target boards.
401 @item @b{olimex-jtag}
402 @* See: @url{http://www.olimex.com}
403 @item @b{Flyswatter/Flyswatter2}
404 @* See: @url{http://www.tincantools.com}
405 @item @b{turtelizer2}
406 @* See:
407 @uref{http://www.ethernut.de/en/hardware/turtelizer/index.html, Turtelizer 2}, or
408 @url{http://www.ethernut.de}
409 @item @b{comstick}
410 @* Link: @url{http://www.hitex.com/index.php?id=383}
411 @item @b{stm32stick}
412 @* Link @url{http://www.hitex.com/stm32-stick}
413 @item @b{axm0432_jtag}
414 @* Axiom AXM-0432 Link @url{http://www.axman.com} - NOTE: This JTAG does not appear
415 to be available anymore as of April 2012.
416 @item @b{cortino}
417 @* Link @url{http://www.hitex.com/index.php?id=cortino}
418 @item @b{dlp-usb1232h}
419 @* Link @url{http://www.dlpdesign.com/usb/usb1232h.shtml}
420 @item @b{digilent-hs1}
421 @* Link @url{http://www.digilentinc.com/Products/Detail.cfm?Prod=JTAG-HS1}
422 @item @b{opendous}
423 @* Link @url{http://code.google.com/p/opendous/wiki/JTAG} FT2232H-based
424 (OpenHardware).
425 @item @b{JTAG-lock-pick Tiny 2}
426 @* Link @url{http://www.distortec.com/jtag-lock-pick-tiny-2} FT232H-based
427
428 @item @b{GW16042}
429 @* Link: @url{http://shop.gateworks.com/index.php?route=product/product&path=70_80&product_id=64}
430 FT2232H-based
431
432 @end itemize
433 @section USB-JTAG / Altera USB-Blaster compatibles
434
435 These devices also show up as FTDI devices, but are not
436 protocol-compatible with the FT2232 devices. They are, however,
437 protocol-compatible among themselves. USB-JTAG devices typically consist
438 of a FT245 followed by a CPLD that understands a particular protocol,
439 or emulates this protocol using some other hardware.
440
441 They may appear under different USB VID/PID depending on the particular
442 product. The driver can be configured to search for any VID/PID pair
443 (see the section on driver commands).
444
445 @itemize
446 @item @b{USB-JTAG} Kolja Waschk's USB Blaster-compatible adapter
447 @* Link: @url{http://ixo-jtag.sourceforge.net/}
448 @item @b{Altera USB-Blaster}
449 @* Link: @url{http://www.altera.com/literature/ug/ug_usb_blstr.pdf}
450 @end itemize
451
452 @section USB J-Link based
453 There are several OEM versions of the SEGGER @b{J-Link} adapter. It is
454 an example of a microcontroller based JTAG adapter, it uses an
455 AT91SAM764 internally.
456
457 @itemize @bullet
458 @item @b{SEGGER J-Link}
459 @* Link: @url{http://www.segger.com/jlink.html}
460 @item @b{Atmel SAM-ICE} (Only works with Atmel chips!)
461 @* Link: @url{http://www.atmel.com/tools/atmelsam-ice.aspx}
462 @item @b{IAR J-Link}
463 @end itemize
464
465 @section USB RLINK based
466 Raisonance has an adapter called @b{RLink}. It exists in a stripped-down form on the STM32 Primer,
467 permanently attached to the JTAG lines. It also exists on the STM32 Primer2, but that is wired for
468 SWD and not JTAG, thus not supported.
469
470 @itemize @bullet
471 @item @b{Raisonance RLink}
472 @* Link: @url{http://www.mcu-raisonance.com/~rlink-debugger-programmer__@/microcontrollers__tool~tool__T018:4cn9ziz4bnx6.html}
473 @item @b{STM32 Primer}
474 @* Link: @url{http://www.stm32circle.com/resources/stm32primer.php}
475 @item @b{STM32 Primer2}
476 @* Link: @url{http://www.stm32circle.com/resources/stm32primer2.php}
477 @end itemize
478
479 @section USB ST-LINK based
480 ST Micro has an adapter called @b{ST-LINK}.
481 They only work with ST Micro chips, notably STM32 and STM8.
482
483 @itemize @bullet
484 @item @b{ST-LINK}
485 @* This is available standalone and as part of some kits, eg. STM32VLDISCOVERY.
486 @* Link: @url{http://www.st.com/internet/evalboard/product/219866.jsp}
487 @item @b{ST-LINK/V2}
488 @* This is available standalone and as part of some kits, eg. STM32F4DISCOVERY.
489 @* Link: @url{http://www.st.com/internet/evalboard/product/251168.jsp}
490 @end itemize
491
492 For info the original ST-LINK enumerates using the mass storage usb class; however,
493 its implementation is completely broken. The result is this causes issues under Linux.
494 The simplest solution is to get Linux to ignore the ST-LINK using one of the following methods:
495 @itemize @bullet
496 @item modprobe -r usb-storage && modprobe usb-storage quirks=483:3744:i
497 @item add "options usb-storage quirks=483:3744:i" to /etc/modprobe.conf
498 @end itemize
499
500 @section USB TI/Stellaris ICDI based
501 Texas Instruments has an adapter called @b{ICDI}.
502 It is not to be confused with the FTDI based adapters that were originally fitted to their
503 evaluation boards. This is the adapter fitted to the Stellaris LaunchPad.
504
505 @section USB CMSIS-DAP based
506 ARM has released a interface standard called CMSIS-DAP that simplifies connecting
507 debuggers to ARM Cortex based targets @url{http://www.keil.com/support/man/docs/dapdebug/dapdebug_introduction.htm}.
508
509 @section USB Other
510 @itemize @bullet
511 @item @b{USBprog}
512 @* Link: @url{http://shop.embedded-projects.net/} - which uses an Atmel MEGA32 and a UBN9604
513
514 @item @b{USB - Presto}
515 @* Link: @url{http://tools.asix.net/prg_presto.htm}
516
517 @item @b{Versaloon-Link}
518 @* Link: @url{http://www.versaloon.com}
519
520 @item @b{ARM-JTAG-EW}
521 @* Link: @url{http://www.olimex.com/dev/arm-jtag-ew.html}
522
523 @item @b{Buspirate}
524 @* Link: @url{http://dangerousprototypes.com/bus-pirate-manual/}
525
526 @item @b{opendous}
527 @* Link: @url{http://code.google.com/p/opendous-jtag/} - which uses an AT90USB162
528
529 @item @b{estick}
530 @* Link: @url{http://code.google.com/p/estick-jtag/}
531
532 @item @b{Keil ULINK v1}
533 @* Link: @url{http://www.keil.com/ulink1/}
534 @end itemize
535
536 @section IBM PC Parallel Printer Port Based
537
538 The two well-known ``JTAG Parallel Ports'' cables are the Xilinx DLC5
539 and the Macraigor Wiggler. There are many clones and variations of
540 these on the market.
541
542 Note that parallel ports are becoming much less common, so if you
543 have the choice you should probably avoid these adapters in favor
544 of USB-based ones.
545
546 @itemize @bullet
547
548 @item @b{Wiggler} - There are many clones of this.
549 @* Link: @url{http://www.macraigor.com/wiggler.htm}
550
551 @item @b{DLC5} - From XILINX - There are many clones of this
552 @* Link: Search the web for: ``XILINX DLC5'' - it is no longer
553 produced, PDF schematics are easily found and it is easy to make.
554
555 @item @b{Amontec - JTAG Accelerator}
556 @* Link: @url{http://www.amontec.com/jtag_accelerator.shtml}
557
558 @item @b{Wiggler2}
559 @* Link: @url{http://www.ccac.rwth-aachen.de/~michaels/index.php/hardware/armjtag}
560
561 @item @b{Wiggler_ntrst_inverted}
562 @* Yet another variation - See the source code, src/jtag/parport.c
563
564 @item @b{old_amt_wiggler}
565 @* Unknown - probably not on the market today
566
567 @item @b{arm-jtag}
568 @* Link: Most likely @url{http://www.olimex.com/dev/arm-jtag.html} [another wiggler clone]
569
570 @item @b{chameleon}
571 @* Link: @url{http://www.amontec.com/chameleon.shtml}
572
573 @item @b{Triton}
574 @* Unknown.
575
576 @item @b{Lattice}
577 @* ispDownload from Lattice Semiconductor
578 @url{http://www.latticesemi.com/lit/docs/@/devtools/dlcable.pdf}
579
580 @item @b{flashlink}
581 @* From ST Microsystems;
582 @* Link: @url{http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/DM00039500.pdf}
583
584 @end itemize
585
586 @section Other...
587 @itemize @bullet
588
589 @item @b{ep93xx}
590 @* An EP93xx based Linux machine using the GPIO pins directly.
591
592 @item @b{at91rm9200}
593 @* Like the EP93xx - but an ATMEL AT91RM9200 based solution using the GPIO pins on the chip.
594
595 @item @b{bcm2835gpio}
596 @* A BCM2835-based board (e.g. Raspberry Pi) using the GPIO pins of the expansion header.
597
598 @item @b{imx_gpio}
599 @* A NXP i.MX-based board (e.g. Wandboard) using the GPIO pins (should work on any i.MX processor).
600
601 @item @b{jtag_vpi}
602 @* A JTAG driver acting as a client for the JTAG VPI server interface.
603 @* Link: @url{http://github.com/fjullien/jtag_vpi}
604
605 @end itemize
606
607 @node About Jim-Tcl
608 @chapter About Jim-Tcl
609 @cindex Jim-Tcl
610 @cindex tcl
611
612 OpenOCD uses a small ``Tcl Interpreter'' known as Jim-Tcl.
613 This programming language provides a simple and extensible
614 command interpreter.
615
616 All commands presented in this Guide are extensions to Jim-Tcl.
617 You can use them as simple commands, without needing to learn
618 much of anything about Tcl.
619 Alternatively, you can write Tcl programs with them.
620
621 You can learn more about Jim at its website, @url{http://jim.tcl.tk}.
622 There is an active and responsive community, get on the mailing list
623 if you have any questions. Jim-Tcl maintainers also lurk on the
624 OpenOCD mailing list.
625
626 @itemize @bullet
627 @item @b{Jim vs. Tcl}
628 @* Jim-Tcl is a stripped down version of the well known Tcl language,
629 which can be found here: @url{http://www.tcl.tk}. Jim-Tcl has far
630 fewer features. Jim-Tcl is several dozens of .C files and .H files and
631 implements the basic Tcl command set. In contrast: Tcl 8.6 is a
632 4.2 MB .zip file containing 1540 files.
633
634 @item @b{Missing Features}
635 @* Our practice has been: Add/clone the real Tcl feature if/when
636 needed. We welcome Jim-Tcl improvements, not bloat. Also there
637 are a large number of optional Jim-Tcl features that are not
638 enabled in OpenOCD.
639
640 @item @b{Scripts}
641 @* OpenOCD configuration scripts are Jim-Tcl Scripts. OpenOCD's
642 command interpreter today is a mixture of (newer)
643 Jim-Tcl commands, and the (older) original command interpreter.
644
645 @item @b{Commands}
646 @* At the OpenOCD telnet command line (or via the GDB monitor command) one
647 can type a Tcl for() loop, set variables, etc.
648 Some of the commands documented in this guide are implemented
649 as Tcl scripts, from a @file{startup.tcl} file internal to the server.
650
651 @item @b{Historical Note}
652 @* Jim-Tcl was introduced to OpenOCD in spring 2008. Fall 2010,
653 before OpenOCD 0.5 release, OpenOCD switched to using Jim-Tcl
654 as a Git submodule, which greatly simplified upgrading Jim-Tcl
655 to benefit from new features and bugfixes in Jim-Tcl.
656
657 @item @b{Need a crash course in Tcl?}
658 @*@xref{Tcl Crash Course}.
659 @end itemize
660
661 @node Running
662 @chapter Running
663 @cindex command line options
664 @cindex logfile
665 @cindex directory search
666
667 Properly installing OpenOCD sets up your operating system to grant it access
668 to the debug adapters. On Linux, this usually involves installing a file
669 in @file{/etc/udev/rules.d,} so OpenOCD has permissions. An example rules file
670 that works for many common adapters is shipped with OpenOCD in the
671 @file{contrib} directory. MS-Windows needs
672 complex and confusing driver configuration for every peripheral. Such issues
673 are unique to each operating system, and are not detailed in this User's Guide.
674
675 Then later you will invoke the OpenOCD server, with various options to
676 tell it how each debug session should work.
677 The @option{--help} option shows:
678 @verbatim
679 bash$ openocd --help
680
681 --help | -h display this help
682 --version | -v display OpenOCD version
683 --file | -f use configuration file <name>
684 --search | -s dir to search for config files and scripts
685 --debug | -d set debug level to 3
686 | -d<n> set debug level to <level>
687 --log_output | -l redirect log output to file <name>
688 --command | -c run <command>
689 @end verbatim
690
691 If you don't give any @option{-f} or @option{-c} options,
692 OpenOCD tries to read the configuration file @file{openocd.cfg}.
693 To specify one or more different
694 configuration files, use @option{-f} options. For example:
695
696 @example
697 openocd -f config1.cfg -f config2.cfg -f config3.cfg
698 @end example
699
700 Configuration files and scripts are searched for in
701 @enumerate
702 @item the current directory,
703 @item any search dir specified on the command line using the @option{-s} option,
704 @item any search dir specified using the @command{add_script_search_dir} command,
705 @item @file{$HOME/.openocd} (not on Windows),
706 @item a directory in the @env{OPENOCD_SCRIPTS} environment variable (if set),
707 @item the site wide script library @file{$pkgdatadir/site} and
708 @item the OpenOCD-supplied script library @file{$pkgdatadir/scripts}.
709 @end enumerate
710 The first found file with a matching file name will be used.
711
712 @quotation Note
713 Don't try to use configuration script names or paths which
714 include the "#" character. That character begins Tcl comments.
715 @end quotation
716
717 @section Simple setup, no customization
718
719 In the best case, you can use two scripts from one of the script
720 libraries, hook up your JTAG adapter, and start the server ... and
721 your JTAG setup will just work "out of the box". Always try to
722 start by reusing those scripts, but assume you'll need more
723 customization even if this works. @xref{OpenOCD Project Setup}.
724
725 If you find a script for your JTAG adapter, and for your board or
726 target, you may be able to hook up your JTAG adapter then start
727 the server with some variation of one of the following:
728
729 @example
730 openocd -f interface/ADAPTER.cfg -f board/MYBOARD.cfg
731 openocd -f interface/ftdi/ADAPTER.cfg -f board/MYBOARD.cfg
732 @end example
733
734 You might also need to configure which reset signals are present,
735 using @option{-c 'reset_config trst_and_srst'} or something similar.
736 If all goes well you'll see output something like
737
738 @example
739 Open On-Chip Debugger 0.4.0 (2010-01-14-15:06)
740 For bug reports, read
741 http://openocd.org/doc/doxygen/bugs.html
742 Info : JTAG tap: lm3s.cpu tap/device found: 0x3ba00477
743 (mfg: 0x23b, part: 0xba00, ver: 0x3)
744 @end example
745
746 Seeing that "tap/device found" message, and no warnings, means
747 the JTAG communication is working. That's a key milestone, but
748 you'll probably need more project-specific setup.
749
750 @section What OpenOCD does as it starts
751
752 OpenOCD starts by processing the configuration commands provided
753 on the command line or, if there were no @option{-c command} or
754 @option{-f file.cfg} options given, in @file{openocd.cfg}.
755 @xref{configurationstage,,Configuration Stage}.
756 At the end of the configuration stage it verifies the JTAG scan
757 chain defined using those commands; your configuration should
758 ensure that this always succeeds.
759 Normally, OpenOCD then starts running as a server.
760 Alternatively, commands may be used to terminate the configuration
761 stage early, perform work (such as updating some flash memory),
762 and then shut down without acting as a server.
763
764 Once OpenOCD starts running as a server, it waits for connections from
765 clients (Telnet, GDB, RPC) and processes the commands issued through
766 those channels.
767
768 If you are having problems, you can enable internal debug messages via
769 the @option{-d} option.
770
771 Also it is possible to interleave Jim-Tcl commands w/config scripts using the
772 @option{-c} command line switch.
773
774 To enable debug output (when reporting problems or working on OpenOCD
775 itself), use the @option{-d} command line switch. This sets the
776 @option{debug_level} to "3", outputting the most information,
777 including debug messages. The default setting is "2", outputting only
778 informational messages, warnings and errors. You can also change this
779 setting from within a telnet or gdb session using @command{debug_level<n>}
780 (@pxref{debuglevel,,debug_level}).
781
782 You can redirect all output from the server to a file using the
783 @option{-l <logfile>} switch.
784
785 Note! OpenOCD will launch the GDB & telnet server even if it can not
786 establish a connection with the target. In general, it is possible for
787 the JTAG controller to be unresponsive until the target is set up
788 correctly via e.g. GDB monitor commands in a GDB init script.
789
790 @node OpenOCD Project Setup
791 @chapter OpenOCD Project Setup
792
793 To use OpenOCD with your development projects, you need to do more than
794 just connect the JTAG adapter hardware (dongle) to your development board
795 and start the OpenOCD server.
796 You also need to configure your OpenOCD server so that it knows
797 about your adapter and board, and helps your work.
798 You may also want to connect OpenOCD to GDB, possibly
799 using Eclipse or some other GUI.
800
801 @section Hooking up the JTAG Adapter
802
803 Today's most common case is a dongle with a JTAG cable on one side
804 (such as a ribbon cable with a 10-pin or 20-pin IDC connector)
805 and a USB cable on the other.
806 Instead of USB, some cables use Ethernet;
807 older ones may use a PC parallel port, or even a serial port.
808
809 @enumerate
810 @item @emph{Start with power to your target board turned off},
811 and nothing connected to your JTAG adapter.
812 If you're particularly paranoid, unplug power to the board.
813 It's important to have the ground signal properly set up,
814 unless you are using a JTAG adapter which provides
815 galvanic isolation between the target board and the
816 debugging host.
817
818 @item @emph{Be sure it's the right kind of JTAG connector.}
819 If your dongle has a 20-pin ARM connector, you need some kind
820 of adapter (or octopus, see below) to hook it up to
821 boards using 14-pin or 10-pin connectors ... or to 20-pin
822 connectors which don't use ARM's pinout.
823
824 In the same vein, make sure the voltage levels are compatible.
825 Not all JTAG adapters have the level shifters needed to work
826 with 1.2 Volt boards.
827
828 @item @emph{Be certain the cable is properly oriented} or you might
829 damage your board. In most cases there are only two possible
830 ways to connect the cable.
831 Connect the JTAG cable from your adapter to the board.
832 Be sure it's firmly connected.
833
834 In the best case, the connector is keyed to physically
835 prevent you from inserting it wrong.
836 This is most often done using a slot on the board's male connector
837 housing, which must match a key on the JTAG cable's female connector.
838 If there's no housing, then you must look carefully and
839 make sure pin 1 on the cable hooks up to pin 1 on the board.
840 Ribbon cables are frequently all grey except for a wire on one
841 edge, which is red. The red wire is pin 1.
842
843 Sometimes dongles provide cables where one end is an ``octopus'' of
844 color coded single-wire connectors, instead of a connector block.
845 These are great when converting from one JTAG pinout to another,
846 but are tedious to set up.
847 Use these with connector pinout diagrams to help you match up the
848 adapter signals to the right board pins.
849
850 @item @emph{Connect the adapter's other end} once the JTAG cable is connected.
851 A USB, parallel, or serial port connector will go to the host which
852 you are using to run OpenOCD.
853 For Ethernet, consult the documentation and your network administrator.
854
855 For USB-based JTAG adapters you have an easy sanity check at this point:
856 does the host operating system see the JTAG adapter? If you're running
857 Linux, try the @command{lsusb} command. If that host is an
858 MS-Windows host, you'll need to install a driver before OpenOCD works.
859
860 @item @emph{Connect the adapter's power supply, if needed.}
861 This step is primarily for non-USB adapters,
862 but sometimes USB adapters need extra power.
863
864 @item @emph{Power up the target board.}
865 Unless you just let the magic smoke escape,
866 you're now ready to set up the OpenOCD server
867 so you can use JTAG to work with that board.
868
869 @end enumerate
870
871 Talk with the OpenOCD server using
872 telnet (@code{telnet localhost 4444} on many systems) or GDB.
873 @xref{GDB and OpenOCD}.
874
875 @section Project Directory
876
877 There are many ways you can configure OpenOCD and start it up.
878
879 A simple way to organize them all involves keeping a
880 single directory for your work with a given board.
881 When you start OpenOCD from that directory,
882 it searches there first for configuration files, scripts,
883 files accessed through semihosting,
884 and for code you upload to the target board.
885 It is also the natural place to write files,
886 such as log files and data you download from the board.
887
888 @section Configuration Basics
889
890 There are two basic ways of configuring OpenOCD, and
891 a variety of ways you can mix them.
892 Think of the difference as just being how you start the server:
893
894 @itemize
895 @item Many @option{-f file} or @option{-c command} options on the command line
896 @item No options, but a @dfn{user config file}
897 in the current directory named @file{openocd.cfg}
898 @end itemize
899
900 Here is an example @file{openocd.cfg} file for a setup
901 using a Signalyzer FT2232-based JTAG adapter to talk to
902 a board with an Atmel AT91SAM7X256 microcontroller:
903
904 @example
905 source [find interface/ftdi/signalyzer.cfg]
906
907 # GDB can also flash my flash!
908 gdb_memory_map enable
909 gdb_flash_program enable
910
911 source [find target/sam7x256.cfg]
912 @end example
913
914 Here is the command line equivalent of that configuration:
915
916 @example
917 openocd -f interface/ftdi/signalyzer.cfg \
918 -c "gdb_memory_map enable" \
919 -c "gdb_flash_program enable" \
920 -f target/sam7x256.cfg
921 @end example
922
923 You could wrap such long command lines in shell scripts,
924 each supporting a different development task.
925 One might re-flash the board with a specific firmware version.
926 Another might set up a particular debugging or run-time environment.
927
928 @quotation Important
929 At this writing (October 2009) the command line method has
930 problems with how it treats variables.
931 For example, after @option{-c "set VAR value"}, or doing the
932 same in a script, the variable @var{VAR} will have no value
933 that can be tested in a later script.
934 @end quotation
935
936 Here we will focus on the simpler solution: one user config
937 file, including basic configuration plus any TCL procedures
938 to simplify your work.
939
940 @section User Config Files
941 @cindex config file, user
942 @cindex user config file
943 @cindex config file, overview
944
945 A user configuration file ties together all the parts of a project
946 in one place.
947 One of the following will match your situation best:
948
949 @itemize
950 @item Ideally almost everything comes from configuration files
951 provided by someone else.
952 For example, OpenOCD distributes a @file{scripts} directory
953 (probably in @file{/usr/share/openocd/scripts} on Linux).
954 Board and tool vendors can provide these too, as can individual
955 user sites; the @option{-s} command line option lets you say
956 where to find these files. (@xref{Running}.)
957 The AT91SAM7X256 example above works this way.
958
959 Three main types of non-user configuration file each have their
960 own subdirectory in the @file{scripts} directory:
961
962 @enumerate
963 @item @b{interface} -- one for each different debug adapter;
964 @item @b{board} -- one for each different board
965 @item @b{target} -- the chips which integrate CPUs and other JTAG TAPs
966 @end enumerate
967
968 Best case: include just two files, and they handle everything else.
969 The first is an interface config file.
970 The second is board-specific, and it sets up the JTAG TAPs and
971 their GDB targets (by deferring to some @file{target.cfg} file),
972 declares all flash memory, and leaves you nothing to do except
973 meet your deadline:
974
975 @example
976 source [find interface/olimex-jtag-tiny.cfg]
977 source [find board/csb337.cfg]
978 @end example
979
980 Boards with a single microcontroller often won't need more
981 than the target config file, as in the AT91SAM7X256 example.
982 That's because there is no external memory (flash, DDR RAM), and
983 the board differences are encapsulated by application code.
984
985 @item Maybe you don't know yet what your board looks like to JTAG.
986 Once you know the @file{interface.cfg} file to use, you may
987 need help from OpenOCD to discover what's on the board.
988 Once you find the JTAG TAPs, you can just search for appropriate
989 target and board
990 configuration files ... or write your own, from the bottom up.
991 @xref{autoprobing,,Autoprobing}.
992
993 @item You can often reuse some standard config files but
994 need to write a few new ones, probably a @file{board.cfg} file.
995 You will be using commands described later in this User's Guide,
996 and working with the guidelines in the next chapter.
997
998 For example, there may be configuration files for your JTAG adapter
999 and target chip, but you need a new board-specific config file
1000 giving access to your particular flash chips.
1001 Or you might need to write another target chip configuration file
1002 for a new chip built around the Cortex-M3 core.
1003
1004 @quotation Note
1005 When you write new configuration files, please submit
1006 them for inclusion in the next OpenOCD release.
1007 For example, a @file{board/newboard.cfg} file will help the
1008 next users of that board, and a @file{target/newcpu.cfg}
1009 will help support users of any board using that chip.
1010 @end quotation
1011
1012 @item
1013 You may may need to write some C code.
1014 It may be as simple as supporting a new FT2232 or parport
1015 based adapter; a bit more involved, like a NAND or NOR flash
1016 controller driver; or a big piece of work like supporting
1017 a new chip architecture.
1018 @end itemize
1019
1020 Reuse the existing config files when you can.
1021 Look first in the @file{scripts/boards} area, then @file{scripts/targets}.
1022 You may find a board configuration that's a good example to follow.
1023
1024 When you write config files, separate the reusable parts
1025 (things every user of that interface, chip, or board needs)
1026 from ones specific to your environment and debugging approach.
1027 @itemize
1028
1029 @item
1030 For example, a @code{gdb-attach} event handler that invokes
1031 the @command{reset init} command will interfere with debugging
1032 early boot code, which performs some of the same actions
1033 that the @code{reset-init} event handler does.
1034
1035 @item
1036 Likewise, the @command{arm9 vector_catch} command (or
1037 @cindex vector_catch
1038 its siblings @command{xscale vector_catch}
1039 and @command{cortex_m vector_catch}) can be a timesaver
1040 during some debug sessions, but don't make everyone use that either.
1041 Keep those kinds of debugging aids in your user config file,
1042 along with messaging and tracing setup.
1043 (@xref{softwaredebugmessagesandtracing,,Software Debug Messages and Tracing}.)
1044
1045 @item
1046 You might need to override some defaults.
1047 For example, you might need to move, shrink, or back up the target's
1048 work area if your application needs much SRAM.
1049
1050 @item
1051 TCP/IP port configuration is another example of something which
1052 is environment-specific, and should only appear in
1053 a user config file. @xref{tcpipports,,TCP/IP Ports}.
1054 @end itemize
1055
1056 @section Project-Specific Utilities
1057
1058 A few project-specific utility
1059 routines may well speed up your work.
1060 Write them, and keep them in your project's user config file.
1061
1062 For example, if you are making a boot loader work on a
1063 board, it's nice to be able to debug the ``after it's
1064 loaded to RAM'' parts separately from the finicky early
1065 code which sets up the DDR RAM controller and clocks.
1066 A script like this one, or a more GDB-aware sibling,
1067 may help:
1068
1069 @example
1070 proc ramboot @{ @} @{
1071 # Reset, running the target's "reset-init" scripts
1072 # to initialize clocks and the DDR RAM controller.
1073 # Leave the CPU halted.
1074 reset init
1075
1076 # Load CONFIG_SKIP_LOWLEVEL_INIT version into DDR RAM.
1077 load_image u-boot.bin 0x20000000
1078
1079 # Start running.
1080 resume 0x20000000
1081 @}
1082 @end example
1083
1084 Then once that code is working you will need to make it
1085 boot from NOR flash; a different utility would help.
1086 Alternatively, some developers write to flash using GDB.
1087 (You might use a similar script if you're working with a flash
1088 based microcontroller application instead of a boot loader.)
1089
1090 @example
1091 proc newboot @{ @} @{
1092 # Reset, leaving the CPU halted. The "reset-init" event
1093 # proc gives faster access to the CPU and to NOR flash;
1094 # "reset halt" would be slower.
1095 reset init
1096
1097 # Write standard version of U-Boot into the first two
1098 # sectors of NOR flash ... the standard version should
1099 # do the same lowlevel init as "reset-init".
1100 flash protect 0 0 1 off
1101 flash erase_sector 0 0 1
1102 flash write_bank 0 u-boot.bin 0x0
1103 flash protect 0 0 1 on
1104
1105 # Reboot from scratch using that new boot loader.
1106 reset run
1107 @}
1108 @end example
1109
1110 You may need more complicated utility procedures when booting
1111 from NAND.
1112 That often involves an extra bootloader stage,
1113 running from on-chip SRAM to perform DDR RAM setup so it can load
1114 the main bootloader code (which won't fit into that SRAM).
1115
1116 Other helper scripts might be used to write production system images,
1117 involving considerably more than just a three stage bootloader.
1118
1119 @section Target Software Changes
1120
1121 Sometimes you may want to make some small changes to the software
1122 you're developing, to help make JTAG debugging work better.
1123 For example, in C or assembly language code you might
1124 use @code{#ifdef JTAG_DEBUG} (or its converse) around code
1125 handling issues like:
1126
1127 @itemize @bullet
1128
1129 @item @b{Watchdog Timers}...
1130 Watchog timers are typically used to automatically reset systems if
1131 some application task doesn't periodically reset the timer. (The
1132 assumption is that the system has locked up if the task can't run.)
1133 When a JTAG debugger halts the system, that task won't be able to run
1134 and reset the timer ... potentially causing resets in the middle of
1135 your debug sessions.
1136
1137 It's rarely a good idea to disable such watchdogs, since their usage
1138 needs to be debugged just like all other parts of your firmware.
1139 That might however be your only option.
1140
1141 Look instead for chip-specific ways to stop the watchdog from counting
1142 while the system is in a debug halt state. It may be simplest to set
1143 that non-counting mode in your debugger startup scripts. You may however
1144 need a different approach when, for example, a motor could be physically
1145 damaged by firmware remaining inactive in a debug halt state. That might
1146 involve a type of firmware mode where that "non-counting" mode is disabled
1147 at the beginning then re-enabled at the end; a watchdog reset might fire
1148 and complicate the debug session, but hardware (or people) would be
1149 protected.@footnote{Note that many systems support a "monitor mode" debug
1150 that is a somewhat cleaner way to address such issues. You can think of
1151 it as only halting part of the system, maybe just one task,
1152 instead of the whole thing.
1153 At this writing, January 2010, OpenOCD based debugging does not support
1154 monitor mode debug, only "halt mode" debug.}
1155
1156 @item @b{ARM Semihosting}...
1157 @cindex ARM semihosting
1158 When linked with a special runtime library provided with many
1159 toolchains@footnote{See chapter 8 "Semihosting" in
1160 @uref{http://infocenter.arm.com/help/topic/com.arm.doc.dui0203i/DUI0203I_rvct_developer_guide.pdf,
1161 ARM DUI 0203I}, the "RealView Compilation Tools Developer Guide".
1162 The CodeSourcery EABI toolchain also includes a semihosting library.},
1163 your target code can use I/O facilities on the debug host. That library
1164 provides a small set of system calls which are handled by OpenOCD.
1165 It can let the debugger provide your system console and a file system,
1166 helping with early debugging or providing a more capable environment
1167 for sometimes-complex tasks like installing system firmware onto
1168 NAND or SPI flash.
1169
1170 @item @b{ARM Wait-For-Interrupt}...
1171 Many ARM chips synchronize the JTAG clock using the core clock.
1172 Low power states which stop that core clock thus prevent JTAG access.
1173 Idle loops in tasking environments often enter those low power states
1174 via the @code{WFI} instruction (or its coprocessor equivalent, before ARMv7).
1175
1176 You may want to @emph{disable that instruction} in source code,
1177 or otherwise prevent using that state,
1178 to ensure you can get JTAG access at any time.@footnote{As a more
1179 polite alternative, some processors have special debug-oriented
1180 registers which can be used to change various features including
1181 how the low power states are clocked while debugging.
1182 The STM32 DBGMCU_CR register is an example; at the cost of extra
1183 power consumption, JTAG can be used during low power states.}
1184 For example, the OpenOCD @command{halt} command may not
1185 work for an idle processor otherwise.
1186
1187 @item @b{Delay after reset}...
1188 Not all chips have good support for debugger access
1189 right after reset; many LPC2xxx chips have issues here.
1190 Similarly, applications that reconfigure pins used for
1191 JTAG access as they start will also block debugger access.
1192
1193 To work with boards like this, @emph{enable a short delay loop}
1194 the first thing after reset, before "real" startup activities.
1195 For example, one second's delay is usually more than enough
1196 time for a JTAG debugger to attach, so that
1197 early code execution can be debugged
1198 or firmware can be replaced.
1199
1200 @item @b{Debug Communications Channel (DCC)}...
1201 Some processors include mechanisms to send messages over JTAG.
1202 Many ARM cores support these, as do some cores from other vendors.
1203 (OpenOCD may be able to use this DCC internally, speeding up some
1204 operations like writing to memory.)
1205
1206 Your application may want to deliver various debugging messages
1207 over JTAG, by @emph{linking with a small library of code}
1208 provided with OpenOCD and using the utilities there to send
1209 various kinds of message.
1210 @xref{softwaredebugmessagesandtracing,,Software Debug Messages and Tracing}.
1211
1212 @end itemize
1213
1214 @section Target Hardware Setup
1215
1216 Chip vendors often provide software development boards which
1217 are highly configurable, so that they can support all options
1218 that product boards may require. @emph{Make sure that any
1219 jumpers or switches match the system configuration you are
1220 working with.}
1221
1222 Common issues include:
1223
1224 @itemize @bullet
1225
1226 @item @b{JTAG setup} ...
1227 Boards may support more than one JTAG configuration.
1228 Examples include jumpers controlling pullups versus pulldowns
1229 on the nTRST and/or nSRST signals, and choice of connectors
1230 (e.g. which of two headers on the base board,
1231 or one from a daughtercard).
1232 For some Texas Instruments boards, you may need to jumper the
1233 EMU0 and EMU1 signals (which OpenOCD won't currently control).
1234
1235 @item @b{Boot Modes} ...
1236 Complex chips often support multiple boot modes, controlled
1237 by external jumpers. Make sure this is set up correctly.
1238 For example many i.MX boards from NXP need to be jumpered
1239 to "ATX mode" to start booting using the on-chip ROM, when
1240 using second stage bootloader code stored in a NAND flash chip.
1241
1242 Such explicit configuration is common, and not limited to
1243 booting from NAND. You might also need to set jumpers to
1244 start booting using code loaded from an MMC/SD card; external
1245 SPI flash; Ethernet, UART, or USB links; NOR flash; OneNAND
1246 flash; some external host; or various other sources.
1247
1248
1249 @item @b{Memory Addressing} ...
1250 Boards which support multiple boot modes may also have jumpers
1251 to configure memory addressing. One board, for example, jumpers
1252 external chipselect 0 (used for booting) to address either
1253 a large SRAM (which must be pre-loaded via JTAG), NOR flash,
1254 or NAND flash. When it's jumpered to address NAND flash, that
1255 board must also be told to start booting from on-chip ROM.
1256
1257 Your @file{board.cfg} file may also need to be told this jumper
1258 configuration, so that it can know whether to declare NOR flash
1259 using @command{flash bank} or instead declare NAND flash with
1260 @command{nand device}; and likewise which probe to perform in
1261 its @code{reset-init} handler.
1262
1263 A closely related issue is bus width. Jumpers might need to
1264 distinguish between 8 bit or 16 bit bus access for the flash
1265 used to start booting.
1266
1267 @item @b{Peripheral Access} ...
1268 Development boards generally provide access to every peripheral
1269 on the chip, sometimes in multiple modes (such as by providing
1270 multiple audio codec chips).
1271 This interacts with software
1272 configuration of pin multiplexing, where for example a
1273 given pin may be routed either to the MMC/SD controller
1274 or the GPIO controller. It also often interacts with
1275 configuration jumpers. One jumper may be used to route
1276 signals to an MMC/SD card slot or an expansion bus (which
1277 might in turn affect booting); others might control which
1278 audio or video codecs are used.
1279
1280 @end itemize
1281
1282 Plus you should of course have @code{reset-init} event handlers
1283 which set up the hardware to match that jumper configuration.
1284 That includes in particular any oscillator or PLL used to clock
1285 the CPU, and any memory controllers needed to access external
1286 memory and peripherals. Without such handlers, you won't be
1287 able to access those resources without working target firmware
1288 which can do that setup ... this can be awkward when you're
1289 trying to debug that target firmware. Even if there's a ROM
1290 bootloader which handles a few issues, it rarely provides full
1291 access to all board-specific capabilities.
1292
1293
1294 @node Config File Guidelines
1295 @chapter Config File Guidelines
1296
1297 This chapter is aimed at any user who needs to write a config file,
1298 including developers and integrators of OpenOCD and any user who
1299 needs to get a new board working smoothly.
1300 It provides guidelines for creating those files.
1301
1302 You should find the following directories under
1303 @t{$(INSTALLDIR)/scripts}, with config files maintained upstream. Use
1304 them as-is where you can; or as models for new files.
1305 @itemize @bullet
1306 @item @file{interface} ...
1307 These are for debug adapters. Files that specify configuration to use
1308 specific JTAG, SWD and other adapters go here.
1309 @item @file{board} ...
1310 Think Circuit Board, PWA, PCB, they go by many names. Board files
1311 contain initialization items that are specific to a board.
1312
1313 They reuse target configuration files, since the same
1314 microprocessor chips are used on many boards,
1315 but support for external parts varies widely. For
1316 example, the SDRAM initialization sequence for the board, or the type
1317 of external flash and what address it uses. Any initialization
1318 sequence to enable that external flash or SDRAM should be found in the
1319 board file. Boards may also contain multiple targets: two CPUs; or
1320 a CPU and an FPGA.
1321 @item @file{target} ...
1322 Think chip. The ``target'' directory represents the JTAG TAPs
1323 on a chip
1324 which OpenOCD should control, not a board. Two common types of targets
1325 are ARM chips and FPGA or CPLD chips.
1326 When a chip has multiple TAPs (maybe it has both ARM and DSP cores),
1327 the target config file defines all of them.
1328 @item @emph{more} ... browse for other library files which may be useful.
1329 For example, there are various generic and CPU-specific utilities.
1330 @end itemize
1331
1332 The @file{openocd.cfg} user config
1333 file may override features in any of the above files by
1334 setting variables before sourcing the target file, or by adding
1335 commands specific to their situation.
1336
1337 @section Interface Config Files
1338
1339 The user config file
1340 should be able to source one of these files with a command like this:
1341
1342 @example
1343 source [find interface/FOOBAR.cfg]
1344 @end example
1345
1346 A preconfigured interface file should exist for every debug adapter
1347 in use today with OpenOCD.
1348 That said, perhaps some of these config files
1349 have only been used by the developer who created it.
1350
1351 A separate chapter gives information about how to set these up.
1352 @xref{Debug Adapter Configuration}.
1353 Read the OpenOCD source code (and Developer's Guide)
1354 if you have a new kind of hardware interface
1355 and need to provide a driver for it.
1356
1357 @section Board Config Files
1358 @cindex config file, board
1359 @cindex board config file
1360
1361 The user config file
1362 should be able to source one of these files with a command like this:
1363
1364 @example
1365 source [find board/FOOBAR.cfg]
1366 @end example
1367
1368 The point of a board config file is to package everything
1369 about a given board that user config files need to know.
1370 In summary the board files should contain (if present)
1371
1372 @enumerate
1373 @item One or more @command{source [find target/...cfg]} statements
1374 @item NOR flash configuration (@pxref{norconfiguration,,NOR Configuration})
1375 @item NAND flash configuration (@pxref{nandconfiguration,,NAND Configuration})
1376 @item Target @code{reset} handlers for SDRAM and I/O configuration
1377 @item JTAG adapter reset configuration (@pxref{Reset Configuration})
1378 @item All things that are not ``inside a chip''
1379 @end enumerate
1380
1381 Generic things inside target chips belong in target config files,
1382 not board config files. So for example a @code{reset-init} event
1383 handler should know board-specific oscillator and PLL parameters,
1384 which it passes to target-specific utility code.
1385
1386 The most complex task of a board config file is creating such a
1387 @code{reset-init} event handler.
1388 Define those handlers last, after you verify the rest of the board
1389 configuration works.
1390
1391 @subsection Communication Between Config files
1392
1393 In addition to target-specific utility code, another way that
1394 board and target config files communicate is by following a
1395 convention on how to use certain variables.
1396
1397 The full Tcl/Tk language supports ``namespaces'', but Jim-Tcl does not.
1398 Thus the rule we follow in OpenOCD is this: Variables that begin with
1399 a leading underscore are temporary in nature, and can be modified and
1400 used at will within a target configuration file.
1401
1402 Complex board config files can do the things like this,
1403 for a board with three chips:
1404
1405 @example
1406 # Chip #1: PXA270 for network side, big endian
1407 set CHIPNAME network
1408 set ENDIAN big
1409 source [find target/pxa270.cfg]
1410 # on return: _TARGETNAME = network.cpu
1411 # other commands can refer to the "network.cpu" target.
1412 $_TARGETNAME configure .... events for this CPU..
1413
1414 # Chip #2: PXA270 for video side, little endian
1415 set CHIPNAME video
1416 set ENDIAN little
1417 source [find target/pxa270.cfg]
1418 # on return: _TARGETNAME = video.cpu
1419 # other commands can refer to the "video.cpu" target.
1420 $_TARGETNAME configure .... events for this CPU..
1421
1422 # Chip #3: Xilinx FPGA for glue logic
1423 set CHIPNAME xilinx
1424 unset ENDIAN
1425 source [find target/spartan3.cfg]
1426 @end example
1427
1428 That example is oversimplified because it doesn't show any flash memory,
1429 or the @code{reset-init} event handlers to initialize external DRAM
1430 or (assuming it needs it) load a configuration into the FPGA.
1431 Such features are usually needed for low-level work with many boards,
1432 where ``low level'' implies that the board initialization software may
1433 not be working. (That's a common reason to need JTAG tools. Another
1434 is to enable working with microcontroller-based systems, which often
1435 have no debugging support except a JTAG connector.)
1436
1437 Target config files may also export utility functions to board and user
1438 config files. Such functions should use name prefixes, to help avoid
1439 naming collisions.
1440
1441 Board files could also accept input variables from user config files.
1442 For example, there might be a @code{J4_JUMPER} setting used to identify
1443 what kind of flash memory a development board is using, or how to set
1444 up other clocks and peripherals.
1445
1446 @subsection Variable Naming Convention
1447 @cindex variable names
1448
1449 Most boards have only one instance of a chip.
1450 However, it should be easy to create a board with more than
1451 one such chip (as shown above).
1452 Accordingly, we encourage these conventions for naming
1453 variables associated with different @file{target.cfg} files,
1454 to promote consistency and
1455 so that board files can override target defaults.
1456
1457 Inputs to target config files include:
1458
1459 @itemize @bullet
1460 @item @code{CHIPNAME} ...
1461 This gives a name to the overall chip, and is used as part of
1462 tap identifier dotted names.
1463 While the default is normally provided by the chip manufacturer,
1464 board files may need to distinguish between instances of a chip.
1465 @item @code{ENDIAN} ...
1466 By default @option{little} - although chips may hard-wire @option{big}.
1467 Chips that can't change endianness don't need to use this variable.
1468 @item @code{CPUTAPID} ...
1469 When OpenOCD examines the JTAG chain, it can be told verify the
1470 chips against the JTAG IDCODE register.
1471 The target file will hold one or more defaults, but sometimes the
1472 chip in a board will use a different ID (perhaps a newer revision).
1473 @end itemize
1474
1475 Outputs from target config files include:
1476
1477 @itemize @bullet
1478 @item @code{_TARGETNAME} ...
1479 By convention, this variable is created by the target configuration
1480 script. The board configuration file may make use of this variable to
1481 configure things like a ``reset init'' script, or other things
1482 specific to that board and that target.
1483 If the chip has 2 targets, the names are @code{_TARGETNAME0},
1484 @code{_TARGETNAME1}, ... etc.
1485 @end itemize
1486
1487 @subsection The reset-init Event Handler
1488 @cindex event, reset-init
1489 @cindex reset-init handler
1490
1491 Board config files run in the OpenOCD configuration stage;
1492 they can't use TAPs or targets, since they haven't been
1493 fully set up yet.
1494 This means you can't write memory or access chip registers;
1495 you can't even verify that a flash chip is present.
1496 That's done later in event handlers, of which the target @code{reset-init}
1497 handler is one of the most important.
1498
1499 Except on microcontrollers, the basic job of @code{reset-init} event
1500 handlers is setting up flash and DRAM, as normally handled by boot loaders.
1501 Microcontrollers rarely use boot loaders; they run right out of their
1502 on-chip flash and SRAM memory. But they may want to use one of these
1503 handlers too, if just for developer convenience.
1504
1505 @quotation Note
1506 Because this is so very board-specific, and chip-specific, no examples
1507 are included here.
1508 Instead, look at the board config files distributed with OpenOCD.
1509 If you have a boot loader, its source code will help; so will
1510 configuration files for other JTAG tools
1511 (@pxref{translatingconfigurationfiles,,Translating Configuration Files}).
1512 @end quotation
1513
1514 Some of this code could probably be shared between different boards.
1515 For example, setting up a DRAM controller often doesn't differ by
1516 much except the bus width (16 bits or 32?) and memory timings, so a
1517 reusable TCL procedure loaded by the @file{target.cfg} file might take
1518 those as parameters.
1519 Similarly with oscillator, PLL, and clock setup;
1520 and disabling the watchdog.
1521 Structure the code cleanly, and provide comments to help
1522 the next developer doing such work.
1523 (@emph{You might be that next person} trying to reuse init code!)
1524
1525 The last thing normally done in a @code{reset-init} handler is probing
1526 whatever flash memory was configured. For most chips that needs to be
1527 done while the associated target is halted, either because JTAG memory
1528 access uses the CPU or to prevent conflicting CPU access.
1529
1530 @subsection JTAG Clock Rate
1531
1532 Before your @code{reset-init} handler has set up
1533 the PLLs and clocking, you may need to run with
1534 a low JTAG clock rate.
1535 @xref{jtagspeed,,JTAG Speed}.
1536 Then you'd increase that rate after your handler has
1537 made it possible to use the faster JTAG clock.
1538 When the initial low speed is board-specific, for example
1539 because it depends on a board-specific oscillator speed, then
1540 you should probably set it up in the board config file;
1541 if it's target-specific, it belongs in the target config file.
1542
1543 For most ARM-based processors the fastest JTAG clock@footnote{A FAQ
1544 @uref{http://www.arm.com/support/faqdev/4170.html} gives details.}
1545 is one sixth of the CPU clock; or one eighth for ARM11 cores.
1546 Consult chip documentation to determine the peak JTAG clock rate,
1547 which might be less than that.
1548
1549 @quotation Warning
1550 On most ARMs, JTAG clock detection is coupled to the core clock, so
1551 software using a @option{wait for interrupt} operation blocks JTAG access.
1552 Adaptive clocking provides a partial workaround, but a more complete
1553 solution just avoids using that instruction with JTAG debuggers.
1554 @end quotation
1555
1556 If both the chip and the board support adaptive clocking,
1557 use the @command{jtag_rclk}
1558 command, in case your board is used with JTAG adapter which
1559 also supports it. Otherwise use @command{adapter_khz}.
1560 Set the slow rate at the beginning of the reset sequence,
1561 and the faster rate as soon as the clocks are at full speed.
1562
1563 @anchor{theinitboardprocedure}
1564 @subsection The init_board procedure
1565 @cindex init_board procedure
1566
1567 The concept of @code{init_board} procedure is very similar to @code{init_targets}
1568 (@xref{theinittargetsprocedure,,The init_targets procedure}.) - it's a replacement of ``linear''
1569 configuration scripts. This procedure is meant to be executed when OpenOCD enters run stage
1570 (@xref{enteringtherunstage,,Entering the Run Stage},) after @code{init_targets}. The idea to have
1571 separate @code{init_targets} and @code{init_board} procedures is to allow the first one to configure
1572 everything target specific (internal flash, internal RAM, etc.) and the second one to configure
1573 everything board specific (reset signals, chip frequency, reset-init event handler, external memory, etc.).
1574 Additionally ``linear'' board config file will most likely fail when target config file uses
1575 @code{init_targets} scheme (``linear'' script is executed before @code{init} and @code{init_targets} - after),
1576 so separating these two configuration stages is very convenient, as the easiest way to overcome this
1577 problem is to convert board config file to use @code{init_board} procedure. Board config scripts don't
1578 need to override @code{init_targets} defined in target config files when they only need to add some specifics.
1579
1580 Just as @code{init_targets}, the @code{init_board} procedure can be overridden by ``next level'' script (which sources
1581 the original), allowing greater code reuse.
1582
1583 @example
1584 ### board_file.cfg ###
1585
1586 # source target file that does most of the config in init_targets
1587 source [find target/target.cfg]
1588
1589 proc enable_fast_clock @{@} @{
1590 # enables fast on-board clock source
1591 # configures the chip to use it
1592 @}
1593
1594 # initialize only board specifics - reset, clock, adapter frequency
1595 proc init_board @{@} @{
1596 reset_config trst_and_srst trst_pulls_srst
1597
1598 $_TARGETNAME configure -event reset-start @{
1599 adapter_khz 100
1600 @}
1601
1602 $_TARGETNAME configure -event reset-init @{
1603 enable_fast_clock
1604 adapter_khz 10000
1605 @}
1606 @}
1607 @end example
1608
1609 @section Target Config Files
1610 @cindex config file, target
1611 @cindex target config file
1612
1613 Board config files communicate with target config files using
1614 naming conventions as described above, and may source one or
1615 more target config files like this:
1616
1617 @example
1618 source [find target/FOOBAR.cfg]
1619 @end example
1620
1621 The point of a target config file is to package everything
1622 about a given chip that board config files need to know.
1623 In summary the target files should contain
1624
1625 @enumerate
1626 @item Set defaults
1627 @item Add TAPs to the scan chain
1628 @item Add CPU targets (includes GDB support)
1629 @item CPU/Chip/CPU-Core specific features
1630 @item On-Chip flash
1631 @end enumerate
1632
1633 As a rule of thumb, a target file sets up only one chip.
1634 For a microcontroller, that will often include a single TAP,
1635 which is a CPU needing a GDB target, and its on-chip flash.
1636
1637 More complex chips may include multiple TAPs, and the target
1638 config file may need to define them all before OpenOCD
1639 can talk to the chip.
1640 For example, some phone chips have JTAG scan chains that include
1641 an ARM core for operating system use, a DSP,
1642 another ARM core embedded in an image processing engine,
1643 and other processing engines.
1644
1645 @subsection Default Value Boiler Plate Code
1646
1647 All target configuration files should start with code like this,
1648 letting board config files express environment-specific
1649 differences in how things should be set up.
1650
1651 @example
1652 # Boards may override chip names, perhaps based on role,
1653 # but the default should match what the vendor uses
1654 if @{ [info exists CHIPNAME] @} @{
1655 set _CHIPNAME $CHIPNAME
1656 @} else @{
1657 set _CHIPNAME sam7x256
1658 @}
1659
1660 # ONLY use ENDIAN with targets that can change it.
1661 if @{ [info exists ENDIAN] @} @{
1662 set _ENDIAN $ENDIAN
1663 @} else @{
1664 set _ENDIAN little
1665 @}
1666
1667 # TAP identifiers may change as chips mature, for example with
1668 # new revision fields (the "3" here). Pick a good default; you
1669 # can pass several such identifiers to the "jtag newtap" command.
1670 if @{ [info exists CPUTAPID ] @} @{
1671 set _CPUTAPID $CPUTAPID
1672 @} else @{
1673 set _CPUTAPID 0x3f0f0f0f
1674 @}
1675 @end example
1676 @c but 0x3f0f0f0f is for an str73x part ...
1677
1678 @emph{Remember:} Board config files may include multiple target
1679 config files, or the same target file multiple times
1680 (changing at least @code{CHIPNAME}).
1681
1682 Likewise, the target configuration file should define
1683 @code{_TARGETNAME} (or @code{_TARGETNAME0} etc) and
1684 use it later on when defining debug targets:
1685
1686 @example
1687 set _TARGETNAME $_CHIPNAME.cpu
1688 target create $_TARGETNAME arm7tdmi -chain-position $_TARGETNAME
1689 @end example
1690
1691 @subsection Adding TAPs to the Scan Chain
1692 After the ``defaults'' are set up,
1693 add the TAPs on each chip to the JTAG scan chain.
1694 @xref{TAP Declaration}, and the naming convention
1695 for taps.
1696
1697 In the simplest case the chip has only one TAP,
1698 probably for a CPU or FPGA.
1699 The config file for the Atmel AT91SAM7X256
1700 looks (in part) like this:
1701
1702 @example
1703 jtag newtap $_CHIPNAME cpu -irlen 4 -expected-id $_CPUTAPID
1704 @end example
1705
1706 A board with two such at91sam7 chips would be able
1707 to source such a config file twice, with different
1708 values for @code{CHIPNAME}, so
1709 it adds a different TAP each time.
1710
1711 If there are nonzero @option{-expected-id} values,
1712 OpenOCD attempts to verify the actual tap id against those values.
1713 It will issue error messages if there is mismatch, which
1714 can help to pinpoint problems in OpenOCD configurations.
1715
1716 @example
1717 JTAG tap: sam7x256.cpu tap/device found: 0x3f0f0f0f
1718 (Manufacturer: 0x787, Part: 0xf0f0, Version: 0x3)
1719 ERROR: Tap: sam7x256.cpu - Expected id: 0x12345678, Got: 0x3f0f0f0f
1720 ERROR: expected: mfg: 0x33c, part: 0x2345, ver: 0x1
1721 ERROR: got: mfg: 0x787, part: 0xf0f0, ver: 0x3
1722 @end example
1723
1724 There are more complex examples too, with chips that have
1725 multiple TAPs. Ones worth looking at include:
1726
1727 @itemize
1728 @item @file{target/omap3530.cfg} -- with disabled ARM and DSP,
1729 plus a JRC to enable them
1730 @item @file{target/str912.cfg} -- with flash, CPU, and boundary scan
1731 @item @file{target/ti_dm355.cfg} -- with ETM, ARM, and JRC (this JRC
1732 is not currently used)
1733 @end itemize
1734
1735 @subsection Add CPU targets
1736
1737 After adding a TAP for a CPU, you should set it up so that
1738 GDB and other commands can use it.
1739 @xref{CPU Configuration}.
1740 For the at91sam7 example above, the command can look like this;
1741 note that @code{$_ENDIAN} is not needed, since OpenOCD defaults
1742 to little endian, and this chip doesn't support changing that.
1743
1744 @example
1745 set _TARGETNAME $_CHIPNAME.cpu
1746 target create $_TARGETNAME arm7tdmi -chain-position $_TARGETNAME
1747 @end example
1748
1749 Work areas are small RAM areas associated with CPU targets.
1750 They are used by OpenOCD to speed up downloads,
1751 and to download small snippets of code to program flash chips.
1752 If the chip includes a form of ``on-chip-ram'' - and many do - define
1753 a work area if you can.
1754 Again using the at91sam7 as an example, this can look like:
1755
1756 @example
1757 $_TARGETNAME configure -work-area-phys 0x00200000 \
1758 -work-area-size 0x4000 -work-area-backup 0
1759 @end example
1760
1761 @anchor{definecputargetsworkinginsmp}
1762 @subsection Define CPU targets working in SMP
1763 @cindex SMP
1764 After setting targets, you can define a list of targets working in SMP.
1765
1766 @example
1767 set _TARGETNAME_1 $_CHIPNAME.cpu1
1768 set _TARGETNAME_2 $_CHIPNAME.cpu2
1769 target create $_TARGETNAME_1 cortex_a -chain-position $_CHIPNAME.dap \
1770 -coreid 0 -dbgbase $_DAP_DBG1
1771 target create $_TARGETNAME_2 cortex_a -chain-position $_CHIPNAME.dap \
1772 -coreid 1 -dbgbase $_DAP_DBG2
1773 #define 2 targets working in smp.
1774 target smp $_CHIPNAME.cpu2 $_CHIPNAME.cpu1
1775 @end example
1776 In the above example on cortex_a, 2 cpus are working in SMP.
1777 In SMP only one GDB instance is created and :
1778 @itemize @bullet
1779 @item a set of hardware breakpoint sets the same breakpoint on all targets in the list.
1780 @item halt command triggers the halt of all targets in the list.
1781 @item resume command triggers the write context and the restart of all targets in the list.
1782 @item following a breakpoint: the target stopped by the breakpoint is displayed to the GDB session.
1783 @item dedicated GDB serial protocol packets are implemented for switching/retrieving the target
1784 displayed by the GDB session @pxref{usingopenocdsmpwithgdb,,Using OpenOCD SMP with GDB}.
1785 @end itemize
1786
1787 The SMP behaviour can be disabled/enabled dynamically. On cortex_a following
1788 command have been implemented.
1789 @itemize @bullet
1790 @item cortex_a smp_on : enable SMP mode, behaviour is as described above.
1791 @item cortex_a smp_off : disable SMP mode, the current target is the one
1792 displayed in the GDB session, only this target is now controlled by GDB
1793 session. This behaviour is useful during system boot up.
1794 @item cortex_a smp_gdb : display/fix the core id displayed in GDB session see
1795 following example.
1796 @end itemize
1797
1798 @example
1799 >cortex_a smp_gdb
1800 gdb coreid 0 -> -1
1801 #0 : coreid 0 is displayed to GDB ,
1802 #-> -1 : next resume triggers a real resume
1803 > cortex_a smp_gdb 1
1804 gdb coreid 0 -> 1
1805 #0 :coreid 0 is displayed to GDB ,
1806 #->1 : next resume displays coreid 1 to GDB
1807 > resume
1808 > cortex_a smp_gdb
1809 gdb coreid 1 -> 1
1810 #1 :coreid 1 is displayed to GDB ,
1811 #->1 : next resume displays coreid 1 to GDB
1812 > cortex_a smp_gdb -1
1813 gdb coreid 1 -> -1
1814 #1 :coreid 1 is displayed to GDB,
1815 #->-1 : next resume triggers a real resume
1816 @end example
1817
1818
1819 @subsection Chip Reset Setup
1820
1821 As a rule, you should put the @command{reset_config} command
1822 into the board file. Most things you think you know about a
1823 chip can be tweaked by the board.
1824
1825 Some chips have specific ways the TRST and SRST signals are
1826 managed. In the unusual case that these are @emph{chip specific}
1827 and can never be changed by board wiring, they could go here.
1828 For example, some chips can't support JTAG debugging without
1829 both signals.
1830
1831 Provide a @code{reset-assert} event handler if you can.
1832 Such a handler uses JTAG operations to reset the target,
1833 letting this target config be used in systems which don't
1834 provide the optional SRST signal, or on systems where you
1835 don't want to reset all targets at once.
1836 Such a handler might write to chip registers to force a reset,
1837 use a JRC to do that (preferable -- the target may be wedged!),
1838 or force a watchdog timer to trigger.
1839 (For Cortex-M targets, this is not necessary. The target
1840 driver knows how to use trigger an NVIC reset when SRST is
1841 not available.)
1842
1843 Some chips need special attention during reset handling if
1844 they're going to be used with JTAG.
1845 An example might be needing to send some commands right
1846 after the target's TAP has been reset, providing a
1847 @code{reset-deassert-post} event handler that writes a chip
1848 register to report that JTAG debugging is being done.
1849 Another would be reconfiguring the watchdog so that it stops
1850 counting while the core is halted in the debugger.
1851
1852 JTAG clocking constraints often change during reset, and in
1853 some cases target config files (rather than board config files)
1854 are the right places to handle some of those issues.
1855 For example, immediately after reset most chips run using a
1856 slower clock than they will use later.
1857 That means that after reset (and potentially, as OpenOCD
1858 first starts up) they must use a slower JTAG clock rate
1859 than they will use later.
1860 @xref{jtagspeed,,JTAG Speed}.
1861
1862 @quotation Important
1863 When you are debugging code that runs right after chip
1864 reset, getting these issues right is critical.
1865 In particular, if you see intermittent failures when
1866 OpenOCD verifies the scan chain after reset,
1867 look at how you are setting up JTAG clocking.
1868 @end quotation
1869
1870 @anchor{theinittargetsprocedure}
1871 @subsection The init_targets procedure
1872 @cindex init_targets procedure
1873
1874 Target config files can either be ``linear'' (script executed line-by-line when parsed in
1875 configuration stage, @xref{configurationstage,,Configuration Stage},) or they can contain a special
1876 procedure called @code{init_targets}, which will be executed when entering run stage
1877 (after parsing all config files or after @code{init} command, @xref{enteringtherunstage,,Entering the Run Stage}.)
1878 Such procedure can be overriden by ``next level'' script (which sources the original).
1879 This concept faciliates code reuse when basic target config files provide generic configuration
1880 procedures and @code{init_targets} procedure, which can then be sourced and enchanced or changed in
1881 a ``more specific'' target config file. This is not possible with ``linear'' config scripts,
1882 because sourcing them executes every initialization commands they provide.
1883
1884 @example
1885 ### generic_file.cfg ###
1886
1887 proc setup_my_chip @{chip_name flash_size ram_size@} @{
1888 # basic initialization procedure ...
1889 @}
1890
1891 proc init_targets @{@} @{
1892 # initializes generic chip with 4kB of flash and 1kB of RAM
1893 setup_my_chip MY_GENERIC_CHIP 4096 1024
1894 @}
1895
1896 ### specific_file.cfg ###
1897
1898 source [find target/generic_file.cfg]
1899
1900 proc init_targets @{@} @{
1901 # initializes specific chip with 128kB of flash and 64kB of RAM
1902 setup_my_chip MY_CHIP_WITH_128K_FLASH_64KB_RAM 131072 65536
1903 @}
1904 @end example
1905
1906 The easiest way to convert ``linear'' config files to @code{init_targets} version is to
1907 enclose every line of ``code'' (i.e. not @code{source} commands, procedures, etc.) in this procedure.
1908
1909 For an example of this scheme see LPC2000 target config files.
1910
1911 The @code{init_boards} procedure is a similar concept concerning board config files
1912 (@xref{theinitboardprocedure,,The init_board procedure}.)
1913
1914 @anchor{theinittargeteventsprocedure}
1915 @subsection The init_target_events procedure
1916 @cindex init_target_events procedure
1917
1918 A special procedure called @code{init_target_events} is run just after
1919 @code{init_targets} (@xref{theinittargetsprocedure,,The init_targets
1920 procedure}.) and before @code{init_board}
1921 (@xref{theinitboardprocedure,,The init_board procedure}.) It is used
1922 to set up default target events for the targets that do not have those
1923 events already assigned.
1924
1925 @subsection ARM Core Specific Hacks
1926
1927 If the chip has a DCC, enable it. If the chip is an ARM9 with some
1928 special high speed download features - enable it.
1929
1930 If present, the MMU, the MPU and the CACHE should be disabled.
1931
1932 Some ARM cores are equipped with trace support, which permits
1933 examination of the instruction and data bus activity. Trace
1934 activity is controlled through an ``Embedded Trace Module'' (ETM)
1935 on one of the core's scan chains. The ETM emits voluminous data
1936 through a ``trace port''. (@xref{armhardwaretracing,,ARM Hardware Tracing}.)
1937 If you are using an external trace port,
1938 configure it in your board config file.
1939 If you are using an on-chip ``Embedded Trace Buffer'' (ETB),
1940 configure it in your target config file.
1941
1942 @example
1943 etm config $_TARGETNAME 16 normal full etb
1944 etb config $_TARGETNAME $_CHIPNAME.etb
1945 @end example
1946
1947 @subsection Internal Flash Configuration
1948
1949 This applies @b{ONLY TO MICROCONTROLLERS} that have flash built in.
1950
1951 @b{Never ever} in the ``target configuration file'' define any type of
1952 flash that is external to the chip. (For example a BOOT flash on
1953 Chip Select 0.) Such flash information goes in a board file - not
1954 the TARGET (chip) file.
1955
1956 Examples:
1957 @itemize @bullet
1958 @item at91sam7x256 - has 256K flash YES enable it.
1959 @item str912 - has flash internal YES enable it.
1960 @item imx27 - uses boot flash on CS0 - it goes in the board file.
1961 @item pxa270 - again - CS0 flash - it goes in the board file.
1962 @end itemize
1963
1964 @anchor{translatingconfigurationfiles}
1965 @section Translating Configuration Files
1966 @cindex translation
1967 If you have a configuration file for another hardware debugger
1968 or toolset (Abatron, BDI2000, BDI3000, CCS,
1969 Lauterbach, SEGGER, Macraigor, etc.), translating
1970 it into OpenOCD syntax is often quite straightforward. The most tricky
1971 part of creating a configuration script is oftentimes the reset init
1972 sequence where e.g. PLLs, DRAM and the like is set up.
1973
1974 One trick that you can use when translating is to write small
1975 Tcl procedures to translate the syntax into OpenOCD syntax. This
1976 can avoid manual translation errors and make it easier to
1977 convert other scripts later on.
1978
1979 Example of transforming quirky arguments to a simple search and
1980 replace job:
1981
1982 @example
1983 # Lauterbach syntax(?)
1984 #
1985 # Data.Set c15:0x042f %long 0x40000015
1986 #
1987 # OpenOCD syntax when using procedure below.
1988 #
1989 # setc15 0x01 0x00050078
1990
1991 proc setc15 @{regs value@} @{
1992 global TARGETNAME
1993
1994 echo [format "set p15 0x%04x, 0x%08x" $regs $value]
1995
1996 arm mcr 15 [expr ($regs>>12)&0x7] \
1997 [expr ($regs>>0)&0xf] [expr ($regs>>4)&0xf] \
1998 [expr ($regs>>8)&0x7] $value
1999 @}
2000 @end example
2001
2002
2003
2004 @node Server Configuration
2005 @chapter Server Configuration
2006 @cindex initialization
2007 The commands here are commonly found in the openocd.cfg file and are
2008 used to specify what TCP/IP ports are used, and how GDB should be
2009 supported.
2010
2011 @anchor{configurationstage}
2012 @section Configuration Stage
2013 @cindex configuration stage
2014 @cindex config command
2015
2016 When the OpenOCD server process starts up, it enters a
2017 @emph{configuration stage} which is the only time that
2018 certain commands, @emph{configuration commands}, may be issued.
2019 Normally, configuration commands are only available
2020 inside startup scripts.
2021
2022 In this manual, the definition of a configuration command is
2023 presented as a @emph{Config Command}, not as a @emph{Command}
2024 which may be issued interactively.
2025 The runtime @command{help} command also highlights configuration
2026 commands, and those which may be issued at any time.
2027
2028 Those configuration commands include declaration of TAPs,
2029 flash banks,
2030 the interface used for JTAG communication,
2031 and other basic setup.
2032 The server must leave the configuration stage before it
2033 may access or activate TAPs.
2034 After it leaves this stage, configuration commands may no
2035 longer be issued.
2036
2037 @anchor{enteringtherunstage}
2038 @section Entering the Run Stage
2039
2040 The first thing OpenOCD does after leaving the configuration
2041 stage is to verify that it can talk to the scan chain
2042 (list of TAPs) which has been configured.
2043 It will warn if it doesn't find TAPs it expects to find,
2044 or finds TAPs that aren't supposed to be there.
2045 You should see no errors at this point.
2046 If you see errors, resolve them by correcting the
2047 commands you used to configure the server.
2048 Common errors include using an initial JTAG speed that's too
2049 fast, and not providing the right IDCODE values for the TAPs
2050 on the scan chain.
2051
2052 Once OpenOCD has entered the run stage, a number of commands
2053 become available.
2054 A number of these relate to the debug targets you may have declared.
2055 For example, the @command{mww} command will not be available until
2056 a target has been successfuly instantiated.
2057 If you want to use those commands, you may need to force
2058 entry to the run stage.
2059
2060 @deffn {Config Command} init
2061 This command terminates the configuration stage and
2062 enters the run stage. This helps when you need to have
2063 the startup scripts manage tasks such as resetting the target,
2064 programming flash, etc. To reset the CPU upon startup, add "init" and
2065 "reset" at the end of the config script or at the end of the OpenOCD
2066 command line using the @option{-c} command line switch.
2067
2068 If this command does not appear in any startup/configuration file
2069 OpenOCD executes the command for you after processing all
2070 configuration files and/or command line options.
2071
2072 @b{NOTE:} This command normally occurs at or near the end of your
2073 openocd.cfg file to force OpenOCD to ``initialize'' and make the
2074 targets ready. For example: If your openocd.cfg file needs to
2075 read/write memory on your target, @command{init} must occur before
2076 the memory read/write commands. This includes @command{nand probe}.
2077 @end deffn
2078
2079 @deffn {Overridable Procedure} jtag_init
2080 This is invoked at server startup to verify that it can talk
2081 to the scan chain (list of TAPs) which has been configured.
2082
2083 The default implementation first tries @command{jtag arp_init},
2084 which uses only a lightweight JTAG reset before examining the
2085 scan chain.
2086 If that fails, it tries again, using a harder reset
2087 from the overridable procedure @command{init_reset}.
2088
2089 Implementations must have verified the JTAG scan chain before
2090 they return.
2091 This is done by calling @command{jtag arp_init}
2092 (or @command{jtag arp_init-reset}).
2093 @end deffn
2094
2095 @anchor{tcpipports}
2096 @section TCP/IP Ports
2097 @cindex TCP port
2098 @cindex server
2099 @cindex port
2100 @cindex security
2101 The OpenOCD server accepts remote commands in several syntaxes.
2102 Each syntax uses a different TCP/IP port, which you may specify
2103 only during configuration (before those ports are opened).
2104
2105 For reasons including security, you may wish to prevent remote
2106 access using one or more of these ports.
2107 In such cases, just specify the relevant port number as "disabled".
2108 If you disable all access through TCP/IP, you will need to
2109 use the command line @option{-pipe} option.
2110
2111 @deffn {Command} gdb_port [number]
2112 @cindex GDB server
2113 Normally gdb listens to a TCP/IP port, but GDB can also
2114 communicate via pipes(stdin/out or named pipes). The name
2115 "gdb_port" stuck because it covers probably more than 90% of
2116 the normal use cases.
2117
2118 No arguments reports GDB port. "pipe" means listen to stdin
2119 output to stdout, an integer is base port number, "disabled"
2120 disables the gdb server.
2121
2122 When using "pipe", also use log_output to redirect the log
2123 output to a file so as not to flood the stdin/out pipes.
2124
2125 The -p/--pipe option is deprecated and a warning is printed
2126 as it is equivalent to passing in -c "gdb_port pipe; log_output openocd.log".
2127
2128 Any other string is interpreted as named pipe to listen to.
2129 Output pipe is the same name as input pipe, but with 'o' appended,
2130 e.g. /var/gdb, /var/gdbo.
2131
2132 The GDB port for the first target will be the base port, the
2133 second target will listen on gdb_port + 1, and so on.
2134 When not specified during the configuration stage,
2135 the port @var{number} defaults to 3333.
2136
2137 Note: when using "gdb_port pipe", increasing the default remote timeout in
2138 gdb (with 'set remotetimeout') is recommended. An insufficient timeout may
2139 cause initialization to fail with "Unknown remote qXfer reply: OK".
2140
2141 @end deffn
2142
2143 @deffn {Command} tcl_port [number]
2144 Specify or query the port used for a simplified RPC
2145 connection that can be used by clients to issue TCL commands and get the
2146 output from the Tcl engine.
2147 Intended as a machine interface.
2148 When not specified during the configuration stage,
2149 the port @var{number} defaults to 6666.
2150 When specified as "disabled", this service is not activated.
2151 @end deffn
2152
2153 @deffn {Command} telnet_port [number]
2154 Specify or query the
2155 port on which to listen for incoming telnet connections.
2156 This port is intended for interaction with one human through TCL commands.
2157 When not specified during the configuration stage,
2158 the port @var{number} defaults to 4444.
2159 When specified as "disabled", this service is not activated.
2160 @end deffn
2161
2162 @anchor{gdbconfiguration}
2163 @section GDB Configuration
2164 @cindex GDB
2165 @cindex GDB configuration
2166 You can reconfigure some GDB behaviors if needed.
2167 The ones listed here are static and global.
2168 @xref{targetconfiguration,,Target Configuration}, about configuring individual targets.
2169 @xref{targetevents,,Target Events}, about configuring target-specific event handling.
2170
2171 @anchor{gdbbreakpointoverride}
2172 @deffn {Command} gdb_breakpoint_override [@option{hard}|@option{soft}|@option{disable}]
2173 Force breakpoint type for gdb @command{break} commands.
2174 This option supports GDB GUIs which don't
2175 distinguish hard versus soft breakpoints, if the default OpenOCD and
2176 GDB behaviour is not sufficient. GDB normally uses hardware
2177 breakpoints if the memory map has been set up for flash regions.
2178 @end deffn
2179
2180 @anchor{gdbflashprogram}
2181 @deffn {Config Command} gdb_flash_program (@option{enable}|@option{disable})
2182 Set to @option{enable} to cause OpenOCD to program the flash memory when a
2183 vFlash packet is received.
2184 The default behaviour is @option{enable}.
2185 @end deffn
2186
2187 @deffn {Config Command} gdb_memory_map (@option{enable}|@option{disable})
2188 Set to @option{enable} to cause OpenOCD to send the memory configuration to GDB when
2189 requested. GDB will then know when to set hardware breakpoints, and program flash
2190 using the GDB load command. @command{gdb_flash_program enable} must also be enabled
2191 for flash programming to work.
2192 Default behaviour is @option{enable}.
2193 @xref{gdbflashprogram,,gdb_flash_program}.
2194 @end deffn
2195
2196 @deffn {Config Command} gdb_report_data_abort (@option{enable}|@option{disable})
2197 Specifies whether data aborts cause an error to be reported
2198 by GDB memory read packets.
2199 The default behaviour is @option{disable};
2200 use @option{enable} see these errors reported.
2201 @end deffn
2202
2203 @deffn {Config Command} gdb_target_description (@option{enable}|@option{disable})
2204 Set to @option{enable} to cause OpenOCD to send the target descriptions to gdb via qXfer:features:read packet.
2205 The default behaviour is @option{enable}.
2206 @end deffn
2207
2208 @deffn {Command} gdb_save_tdesc
2209 Saves the target descripton file to the local file system.
2210
2211 The file name is @i{target_name}.xml.
2212 @end deffn
2213
2214 @anchor{eventpolling}
2215 @section Event Polling
2216
2217 Hardware debuggers are parts of asynchronous systems,
2218 where significant events can happen at any time.
2219 The OpenOCD server needs to detect some of these events,
2220 so it can report them to through TCL command line
2221 or to GDB.
2222
2223 Examples of such events include:
2224
2225 @itemize
2226 @item One of the targets can stop running ... maybe it triggers
2227 a code breakpoint or data watchpoint, or halts itself.
2228 @item Messages may be sent over ``debug message'' channels ... many
2229 targets support such messages sent over JTAG,
2230 for receipt by the person debugging or tools.
2231 @item Loss of power ... some adapters can detect these events.
2232 @item Resets not issued through JTAG ... such reset sources
2233 can include button presses or other system hardware, sometimes
2234 including the target itself (perhaps through a watchdog).
2235 @item Debug instrumentation sometimes supports event triggering
2236 such as ``trace buffer full'' (so it can quickly be emptied)
2237 or other signals (to correlate with code behavior).
2238 @end itemize
2239
2240 None of those events are signaled through standard JTAG signals.
2241 However, most conventions for JTAG connectors include voltage
2242 level and system reset (SRST) signal detection.
2243 Some connectors also include instrumentation signals, which
2244 can imply events when those signals are inputs.
2245
2246 In general, OpenOCD needs to periodically check for those events,
2247 either by looking at the status of signals on the JTAG connector
2248 or by sending synchronous ``tell me your status'' JTAG requests
2249 to the various active targets.
2250 There is a command to manage and monitor that polling,
2251 which is normally done in the background.
2252
2253 @deffn Command poll [@option{on}|@option{off}]
2254 Poll the current target for its current state.
2255 (Also, @pxref{targetcurstate,,target curstate}.)
2256 If that target is in debug mode, architecture
2257 specific information about the current state is printed.
2258 An optional parameter
2259 allows background polling to be enabled and disabled.
2260
2261 You could use this from the TCL command shell, or
2262 from GDB using @command{monitor poll} command.
2263 Leave background polling enabled while you're using GDB.
2264 @example
2265 > poll
2266 background polling: on
2267 target state: halted
2268 target halted in ARM state due to debug-request, \
2269 current mode: Supervisor
2270 cpsr: 0x800000d3 pc: 0x11081bfc
2271 MMU: disabled, D-Cache: disabled, I-Cache: enabled
2272 >
2273 @end example
2274 @end deffn
2275
2276 @node Debug Adapter Configuration
2277 @chapter Debug Adapter Configuration
2278 @cindex config file, interface
2279 @cindex interface config file
2280
2281 Correctly installing OpenOCD includes making your operating system give
2282 OpenOCD access to debug adapters. Once that has been done, Tcl commands
2283 are used to select which one is used, and to configure how it is used.
2284
2285 @quotation Note
2286 Because OpenOCD started out with a focus purely on JTAG, you may find
2287 places where it wrongly presumes JTAG is the only transport protocol
2288 in use. Be aware that recent versions of OpenOCD are removing that
2289 limitation. JTAG remains more functional than most other transports.
2290 Other transports do not support boundary scan operations, or may be
2291 specific to a given chip vendor. Some might be usable only for
2292 programming flash memory, instead of also for debugging.
2293 @end quotation
2294
2295 Debug Adapters/Interfaces/Dongles are normally configured
2296 through commands in an interface configuration
2297 file which is sourced by your @file{openocd.cfg} file, or
2298 through a command line @option{-f interface/....cfg} option.
2299
2300 @example
2301 source [find interface/olimex-jtag-tiny.cfg]
2302 @end example
2303
2304 These commands tell
2305 OpenOCD what type of JTAG adapter you have, and how to talk to it.
2306 A few cases are so simple that you only need to say what driver to use:
2307
2308 @example
2309 # jlink interface
2310 interface jlink
2311 @end example
2312
2313 Most adapters need a bit more configuration than that.
2314
2315
2316 @section Interface Configuration
2317
2318 The interface command tells OpenOCD what type of debug adapter you are
2319 using. Depending on the type of adapter, you may need to use one or
2320 more additional commands to further identify or configure the adapter.
2321
2322 @deffn {Config Command} {interface} name
2323 Use the interface driver @var{name} to connect to the
2324 target.
2325 @end deffn
2326
2327 @deffn Command {interface_list}
2328 List the debug adapter drivers that have been built into
2329 the running copy of OpenOCD.
2330 @end deffn
2331 @deffn Command {interface transports} transport_name+
2332 Specifies the transports supported by this debug adapter.
2333 The adapter driver builds-in similar knowledge; use this only
2334 when external configuration (such as jumpering) changes what
2335 the hardware can support.
2336 @end deffn
2337
2338
2339
2340 @deffn Command {adapter_name}
2341 Returns the name of the debug adapter driver being used.
2342 @end deffn
2343
2344 @section Interface Drivers
2345
2346 Each of the interface drivers listed here must be explicitly
2347 enabled when OpenOCD is configured, in order to be made
2348 available at run time.
2349
2350 @deffn {Interface Driver} {amt_jtagaccel}
2351 Amontec Chameleon in its JTAG Accelerator configuration,
2352 connected to a PC's EPP mode parallel port.
2353 This defines some driver-specific commands:
2354
2355 @deffn {Config Command} {parport_port} number
2356 Specifies either the address of the I/O port (default: 0x378 for LPT1) or
2357 the number of the @file{/dev/parport} device.
2358 @end deffn
2359
2360 @deffn {Config Command} rtck [@option{enable}|@option{disable}]
2361 Displays status of RTCK option.
2362 Optionally sets that option first.
2363 @end deffn
2364 @end deffn
2365
2366 @deffn {Interface Driver} {arm-jtag-ew}
2367 Olimex ARM-JTAG-EW USB adapter
2368 This has one driver-specific command:
2369
2370 @deffn Command {armjtagew_info}
2371 Logs some status
2372 @end deffn
2373 @end deffn
2374
2375 @deffn {Interface Driver} {at91rm9200}
2376 Supports bitbanged JTAG from the local system,
2377 presuming that system is an Atmel AT91rm9200
2378 and a specific set of GPIOs is used.
2379 @c command: at91rm9200_device NAME
2380 @c chooses among list of bit configs ... only one option
2381 @end deffn
2382
2383 @deffn {Interface Driver} {cmsis-dap}
2384 ARM CMSIS-DAP compliant based adapter.
2385
2386 @deffn {Config Command} {cmsis_dap_vid_pid} [vid pid]+
2387 The vendor ID and product ID of the CMSIS-DAP device. If not specified
2388 the driver will attempt to auto detect the CMSIS-DAP device.
2389 Currently, up to eight [@var{vid}, @var{pid}] pairs may be given, e.g.
2390 @example
2391 cmsis_dap_vid_pid 0xc251 0xf001 0x0d28 0x0204
2392 @end example
2393 @end deffn
2394
2395 @deffn {Config Command} {cmsis_dap_serial} [serial]
2396 Specifies the @var{serial} of the CMSIS-DAP device to use.
2397 If not specified, serial numbers are not considered.
2398 @end deffn
2399
2400 @deffn {Command} {cmsis-dap info}
2401 Display various device information, like hardware version, firmware version, current bus status.
2402 @end deffn
2403 @end deffn
2404
2405 @deffn {Interface Driver} {dummy}
2406 A dummy software-only driver for debugging.
2407 @end deffn
2408
2409 @deffn {Interface Driver} {ep93xx}
2410 Cirrus Logic EP93xx based single-board computer bit-banging (in development)
2411 @end deffn
2412
2413 @deffn {Interface Driver} {ftdi}
2414 This driver is for adapters using the MPSSE (Multi-Protocol Synchronous Serial
2415 Engine) mode built into many FTDI chips, such as the FT2232, FT4232 and FT232H.
2416
2417 The driver is using libusb-1.0 in asynchronous mode to talk to the FTDI device,
2418 bypassing intermediate libraries like libftdi or D2XX.
2419
2420 Support for new FTDI based adapters can be added competely through
2421 configuration files, without the need to patch and rebuild OpenOCD.
2422
2423 The driver uses a signal abstraction to enable Tcl configuration files to
2424 define outputs for one or several FTDI GPIO. These outputs can then be
2425 controlled using the @command{ftdi_set_signal} command. Special signal names
2426 are reserved for nTRST, nSRST and LED (for blink) so that they, if defined,
2427 will be used for their customary purpose. Inputs can be read using the
2428 @command{ftdi_get_signal} command.
2429
2430 To support SWD, a signal named SWD_EN must be defined. It is set to 1 when the
2431 SWD protocol is selected. When set, the adapter should route the SWDIO pin to
2432 the data input. An SWDIO_OE signal, if defined, will be set to 1 or 0 as
2433 required by the protocol, to tell the adapter to drive the data output onto
2434 the SWDIO pin or keep the SWDIO pin Hi-Z, respectively.
2435
2436 Depending on the type of buffer attached to the FTDI GPIO, the outputs have to
2437 be controlled differently. In order to support tristateable signals such as
2438 nSRST, both a data GPIO and an output-enable GPIO can be specified for each
2439 signal. The following output buffer configurations are supported:
2440
2441 @itemize @minus
2442 @item Push-pull with one FTDI output as (non-)inverted data line
2443 @item Open drain with one FTDI output as (non-)inverted output-enable
2444 @item Tristate with one FTDI output as (non-)inverted data line and another
2445 FTDI output as (non-)inverted output-enable
2446 @item Unbuffered, using the FTDI GPIO as a tristate output directly by
2447 switching data and direction as necessary
2448 @end itemize
2449
2450 These interfaces have several commands, used to configure the driver
2451 before initializing the JTAG scan chain:
2452
2453 @deffn {Config Command} {ftdi_vid_pid} [vid pid]+
2454 The vendor ID and product ID of the adapter. Up to eight
2455 [@var{vid}, @var{pid}] pairs may be given, e.g.
2456 @example
2457 ftdi_vid_pid 0x0403 0xcff8 0x15ba 0x0003
2458 @end example
2459 @end deffn
2460
2461 @deffn {Config Command} {ftdi_device_desc} description
2462 Provides the USB device description (the @emph{iProduct string})
2463 of the adapter. If not specified, the device description is ignored
2464 during device selection.
2465 @end deffn
2466
2467 @deffn {Config Command} {ftdi_serial} serial-number
2468 Specifies the @var{serial-number} of the adapter to use,
2469 in case the vendor provides unique IDs and more than one adapter
2470 is connected to the host.
2471 If not specified, serial numbers are not considered.
2472 (Note that USB serial numbers can be arbitrary Unicode strings,
2473 and are not restricted to containing only decimal digits.)
2474 @end deffn
2475
2476 @deffn {Config Command} {ftdi_location} <bus>:<port>[,<port>]...
2477 Specifies the physical USB port of the adapter to use. The path
2478 roots at @var{bus} and walks down the physical ports, with each
2479 @var{port} option specifying a deeper level in the bus topology, the last
2480 @var{port} denoting where the target adapter is actually plugged.
2481 The USB bus topology can be queried with the command @emph{lsusb -t}.
2482
2483 This command is only available if your libusb1 is at least version 1.0.16.
2484 @end deffn
2485
2486 @deffn {Config Command} {ftdi_channel} channel
2487 Selects the channel of the FTDI device to use for MPSSE operations. Most
2488 adapters use the default, channel 0, but there are exceptions.
2489 @end deffn
2490
2491 @deffn {Config Command} {ftdi_layout_init} data direction
2492 Specifies the initial values of the FTDI GPIO data and direction registers.
2493 Each value is a 16-bit number corresponding to the concatenation of the high
2494 and low FTDI GPIO registers. The values should be selected based on the
2495 schematics of the adapter, such that all signals are set to safe levels with
2496 minimal impact on the target system. Avoid floating inputs, conflicting outputs
2497 and initially asserted reset signals.
2498 @end deffn
2499
2500 @deffn {Config Command} {ftdi_layout_signal} name [@option{-data}|@option{-ndata} data_mask] [@option{-input}|@option{-ninput} input_mask] [@option{-oe}|@option{-noe} oe_mask] [@option{-alias}|@option{-nalias} name]
2501 Creates a signal with the specified @var{name}, controlled by one or more FTDI
2502 GPIO pins via a range of possible buffer connections. The masks are FTDI GPIO
2503 register bitmasks to tell the driver the connection and type of the output
2504 buffer driving the respective signal. @var{data_mask} is the bitmask for the
2505 pin(s) connected to the data input of the output buffer. @option{-ndata} is
2506 used with inverting data inputs and @option{-data} with non-inverting inputs.
2507 The @option{-oe} (or @option{-noe}) option tells where the output-enable (or
2508 not-output-enable) input to the output buffer is connected. The options
2509 @option{-input} and @option{-ninput} specify the bitmask for pins to be read
2510 with the method @command{ftdi_get_signal}.
2511
2512 Both @var{data_mask} and @var{oe_mask} need not be specified. For example, a
2513 simple open-collector transistor driver would be specified with @option{-oe}
2514 only. In that case the signal can only be set to drive low or to Hi-Z and the
2515 driver will complain if the signal is set to drive high. Which means that if
2516 it's a reset signal, @command{reset_config} must be specified as
2517 @option{srst_open_drain}, not @option{srst_push_pull}.
2518
2519 A special case is provided when @option{-data} and @option{-oe} is set to the
2520 same bitmask. Then the FTDI pin is considered being connected straight to the
2521 target without any buffer. The FTDI pin is then switched between output and
2522 input as necessary to provide the full set of low, high and Hi-Z
2523 characteristics. In all other cases, the pins specified in a signal definition
2524 are always driven by the FTDI.
2525
2526 If @option{-alias} or @option{-nalias} is used, the signal is created
2527 identical (or with data inverted) to an already specified signal
2528 @var{name}.
2529 @end deffn
2530
2531 @deffn {Command} {ftdi_set_signal} name @option{0}|@option{1}|@option{z}
2532 Set a previously defined signal to the specified level.
2533 @itemize @minus
2534 @item @option{0}, drive low
2535 @item @option{1}, drive high
2536 @item @option{z}, set to high-impedance
2537 @end itemize
2538 @end deffn
2539
2540 @deffn {Command} {ftdi_get_signal} name
2541 Get the value of a previously defined signal.
2542 @end deffn
2543
2544 @deffn {Command} {ftdi_tdo_sample_edge} @option{rising}|@option{falling}
2545 Configure TCK edge at which the adapter samples the value of the TDO signal
2546
2547 Due to signal propagation delays, sampling TDO on rising TCK can become quite
2548 peculiar at high JTAG clock speeds. However, FTDI chips offer a possiblity to sample
2549 TDO on falling edge of TCK. With some board/adapter configurations, this may increase
2550 stability at higher JTAG clocks.
2551 @itemize @minus
2552 @item @option{rising}, sample TDO on rising edge of TCK - this is the default
2553 @item @option{falling}, sample TDO on falling edge of TCK
2554 @end itemize
2555 @end deffn
2556
2557 For example adapter definitions, see the configuration files shipped in the
2558 @file{interface/ftdi} directory.
2559
2560 @end deffn
2561
2562 @deffn {Interface Driver} {remote_bitbang}
2563 Drive JTAG from a remote process. This sets up a UNIX or TCP socket connection
2564 with a remote process and sends ASCII encoded bitbang requests to that process
2565 instead of directly driving JTAG.
2566
2567 The remote_bitbang driver is useful for debugging software running on
2568 processors which are being simulated.
2569
2570 @deffn {Config Command} {remote_bitbang_port} number
2571 Specifies the TCP port of the remote process to connect to or 0 to use UNIX
2572 sockets instead of TCP.
2573 @end deffn
2574
2575 @deffn {Config Command} {remote_bitbang_host} hostname
2576 Specifies the hostname of the remote process to connect to using TCP, or the
2577 name of the UNIX socket to use if remote_bitbang_port is 0.
2578 @end deffn
2579
2580 For example, to connect remotely via TCP to the host foobar you might have
2581 something like:
2582
2583 @example
2584 interface remote_bitbang
2585 remote_bitbang_port 3335
2586 remote_bitbang_host foobar
2587 @end example
2588
2589 To connect to another process running locally via UNIX sockets with socket
2590 named mysocket:
2591
2592 @example
2593 interface remote_bitbang
2594 remote_bitbang_port 0
2595 remote_bitbang_host mysocket
2596 @end example
2597 @end deffn
2598
2599 @deffn {Interface Driver} {usb_blaster}
2600 USB JTAG/USB-Blaster compatibles over one of the userspace libraries
2601 for FTDI chips. These interfaces have several commands, used to
2602 configure the driver before initializing the JTAG scan chain:
2603
2604 @deffn {Config Command} {usb_blaster_device_desc} description
2605 Provides the USB device description (the @emph{iProduct string})
2606 of the FTDI FT245 device. If not
2607 specified, the FTDI default value is used. This setting is only valid
2608 if compiled with FTD2XX support.
2609 @end deffn
2610
2611 @deffn {Config Command} {usb_blaster_vid_pid} vid pid
2612 The vendor ID and product ID of the FTDI FT245 device. If not specified,
2613 default values are used.
2614 Currently, only one @var{vid}, @var{pid} pair may be given, e.g. for
2615 Altera USB-Blaster (default):
2616 @example
2617 usb_blaster_vid_pid 0x09FB 0x6001
2618 @end example
2619 The following VID/PID is for Kolja Waschk's USB JTAG:
2620 @example
2621 usb_blaster_vid_pid 0x16C0 0x06AD
2622 @end example
2623 @end deffn
2624
2625 @deffn {Command} {usb_blaster_pin} (@option{pin6}|@option{pin8}) (@option{0}|@option{1}|@option{s}|@option{t})
2626 Sets the state or function of the unused GPIO pins on USB-Blasters
2627 (pins 6 and 8 on the female JTAG header). These pins can be used as
2628 SRST and/or TRST provided the appropriate connections are made on the
2629 target board.
2630
2631 For example, to use pin 6 as SRST:
2632 @example
2633 usb_blaster_pin pin6 s
2634 reset_config srst_only
2635 @end example
2636 @end deffn
2637
2638 @deffn {Command} {usb_blaster_lowlevel_driver} (@option{ftdi}|@option{ublast2})
2639 Chooses the low level access method for the adapter. If not specified,
2640 @option{ftdi} is selected unless it wasn't enabled during the
2641 configure stage. USB-Blaster II needs @option{ublast2}.
2642 @end deffn
2643
2644 @deffn {Command} {usb_blaster_firmware} @var{path}
2645 This command specifies @var{path} to access USB-Blaster II firmware
2646 image. To be used with USB-Blaster II only.
2647 @end deffn
2648
2649 @end deffn
2650
2651 @deffn {Interface Driver} {gw16012}
2652 Gateworks GW16012 JTAG programmer.
2653 This has one driver-specific command:
2654
2655 @deffn {Config Command} {parport_port} [port_number]
2656 Display either the address of the I/O port
2657 (default: 0x378 for LPT1) or the number of the @file{/dev/parport} device.
2658 If a parameter is provided, first switch to use that port.
2659 This is a write-once setting.
2660 @end deffn
2661 @end deffn
2662
2663 @deffn {Interface Driver} {jlink}
2664 SEGGER J-Link family of USB adapters. It currently supports JTAG and SWD
2665 transports.
2666
2667 @quotation Compatibility Note
2668 SEGGER released many firmware versions for the many harware versions they
2669 produced. OpenOCD was extensively tested and intended to run on all of them,
2670 but some combinations were reported as incompatible. As a general
2671 recommendation, it is advisable to use the latest firmware version
2672 available for each hardware version. However the current V8 is a moving
2673 target, and SEGGER firmware versions released after the OpenOCD was
2674 released may not be compatible. In such cases it is recommended to
2675 revert to the last known functional version. For 0.5.0, this is from
2676 "Feb 8 2012 14:30:39", packed with 4.42c. For 0.6.0, the last known
2677 version is from "May 3 2012 18:36:22", packed with 4.46f.
2678 @end quotation
2679
2680 @deffn {Command} {jlink hwstatus}
2681 Display various hardware related information, for example target voltage and pin
2682 states.
2683 @end deffn
2684 @deffn {Command} {jlink freemem}
2685 Display free device internal memory.
2686 @end deffn
2687 @deffn {Command} {jlink jtag} [@option{2}|@option{3}]
2688 Set the JTAG command version to be used. Without argument, show the actual JTAG
2689 command version.
2690 @end deffn
2691 @deffn {Command} {jlink config}
2692 Display the device configuration.
2693 @end deffn
2694 @deffn {Command} {jlink config targetpower} [@option{on}|@option{off}]
2695 Set the target power state on JTAG-pin 19. Without argument, show the target
2696 power state.
2697 @end deffn
2698 @deffn {Command} {jlink config mac} [@option{ff:ff:ff:ff:ff:ff}]
2699 Set the MAC address of the device. Without argument, show the MAC address.
2700 @end deffn
2701 @deffn {Command} {jlink config ip} [@option{A.B.C.D}(@option{/E}|@option{F.G.H.I})]
2702 Set the IP configuration of the device, where A.B.C.D is the IP address, E the
2703 bit of the subnet mask and F.G.H.I the subnet mask. Without arguments, show the
2704 IP configuration.
2705 @end deffn
2706 @deffn {Command} {jlink config usb} [@option{0} to @option{3}]
2707 Set the USB address of the device. This will also change the USB Product ID
2708 (PID) of the device. Without argument, show the USB address.
2709 @end deffn
2710 @deffn {Command} {jlink config reset}
2711 Reset the current configuration.
2712 @end deffn
2713 @deffn {Command} {jlink config write}
2714 Write the current configuration to the internal persistent storage.
2715 @end deffn
2716 @deffn {Command} {jlink emucom write <channel> <data>}
2717 Write data to an EMUCOM channel. The data needs to be encoded as hexadecimal
2718 pairs.
2719
2720 The following example shows how to write the three bytes 0xaa, 0x0b and 0x23 to
2721 the EMUCOM channel 0x10:
2722 @example
2723 > jlink emucom write 0x10 aa0b23
2724 @end example
2725 @end deffn
2726 @deffn {Command} {jlink emucom read <channel> <length>}
2727 Read data from an EMUCOM channel. The read data is encoded as hexadecimal
2728 pairs.
2729
2730 The following example shows how to read 4 bytes from the EMUCOM channel 0x0:
2731 @example
2732 > jlink emucom read 0x0 4
2733 77a90000
2734 @end example
2735 @end deffn
2736 @deffn {Config} {jlink usb} <@option{0} to @option{3}>
2737 Set the USB address of the interface, in case more than one adapter is connected
2738 to the host. If not specified, USB addresses are not considered. Device
2739 selection via USB address is deprecated and the serial number should be used
2740 instead.
2741
2742 As a configuration command, it can be used only before 'init'.
2743 @end deffn
2744 @deffn {Config} {jlink serial} <serial number>
2745 Set the serial number of the interface, in case more than one adapter is
2746 connected to the host. If not specified, serial numbers are not considered.
2747
2748 As a configuration command, it can be used only before 'init'.
2749 @end deffn
2750 @end deffn
2751
2752 @deffn {Interface Driver} {kitprog}
2753 This driver is for Cypress Semiconductor's KitProg adapters. The KitProg is an
2754 SWD-only adapter that is designed to be used with Cypress's PSoC and PRoC device
2755 families, but it is possible to use it with some other devices. If you are using
2756 this adapter with a PSoC or a PRoC, you may need to add
2757 @command{kitprog_init_acquire_psoc} or @command{kitprog acquire_psoc} to your
2758 configuration script.
2759
2760 Note that this driver is for the proprietary KitProg protocol, not the CMSIS-DAP
2761 mode introduced in firmware 2.14. If the KitProg is in CMSIS-DAP mode, it cannot
2762 be used with this driver, and must either be used with the cmsis-dap driver or
2763 switched back to KitProg mode. See the Cypress KitProg User Guide for
2764 instructions on how to switch KitProg modes.
2765
2766 Known limitations:
2767 @itemize @bullet
2768 @item The frequency of SWCLK cannot be configured, and varies between 1.6 MHz
2769 and 2.7 MHz.
2770 @item For firmware versions below 2.14, "JTAG to SWD" sequences are replaced by
2771 "SWD line reset" in the driver. This is for two reasons. First, the KitProg does
2772 not support sending arbitrary SWD sequences, and only firmware 2.14 and later
2773 implement both "JTAG to SWD" and "SWD line reset" in firmware. Earlier firmware
2774 versions only implement "SWD line reset". Second, due to a firmware quirk, an
2775 SWD sequence must be sent after every target reset in order to re-establish
2776 communications with the target.
2777 @item Due in part to the limitation above, KitProg devices with firmware below
2778 version 2.14 will need to use @command{kitprog_init_acquire_psoc} in order to
2779 communicate with PSoC 5LP devices. This is because, assuming debug is not
2780 disabled on the PSoC, the PSoC 5LP needs its JTAG interface switched to SWD
2781 mode before communication can begin, but prior to firmware 2.14, "JTAG to SWD"
2782 could only be sent with an acquisition sequence.
2783 @end itemize
2784
2785 @deffn {Config Command} {kitprog_init_acquire_psoc}
2786 Indicate that a PSoC acquisition sequence needs to be run during adapter init.
2787 Please be aware that the acquisition sequence hard-resets the target.
2788 @end deffn
2789
2790 @deffn {Config Command} {kitprog_serial} serial
2791 Select a KitProg device by its @var{serial}. If left unspecified, the first
2792 device detected by OpenOCD will be used.
2793 @end deffn
2794
2795 @deffn {Command} {kitprog acquire_psoc}
2796 Run a PSoC acquisition sequence immediately. Typically, this should not be used
2797 outside of the target-specific configuration scripts since it hard-resets the
2798 target as a side-effect.
2799 This is necessary for "reset halt" on some PSoC 4 series devices.
2800 @end deffn
2801
2802 @deffn {Command} {kitprog info}
2803 Display various adapter information, such as the hardware version, firmware
2804 version, and target voltage.
2805 @end deffn
2806 @end deffn
2807
2808 @deffn {Interface Driver} {parport}
2809 Supports PC parallel port bit-banging cables:
2810 Wigglers, PLD download cable, and more.
2811 These interfaces have several commands, used to configure the driver
2812 before initializing the JTAG scan chain:
2813
2814 @deffn {Config Command} {parport_cable} name
2815 Set the layout of the parallel port cable used to connect to the target.
2816 This is a write-once setting.
2817 Currently valid cable @var{name} values include:
2818
2819 @itemize @minus
2820 @item @b{altium} Altium Universal JTAG cable.
2821 @item @b{arm-jtag} Same as original wiggler except SRST and
2822 TRST connections reversed and TRST is also inverted.
2823 @item @b{chameleon} The Amontec Chameleon's CPLD when operated
2824 in configuration mode. This is only used to
2825 program the Chameleon itself, not a connected target.
2826 @item @b{dlc5} The Xilinx Parallel cable III.
2827 @item @b{flashlink} The ST Parallel cable.
2828 @item @b{lattice} Lattice ispDOWNLOAD Cable
2829 @item @b{old_amt_wiggler} The Wiggler configuration that comes with
2830 some versions of
2831 Amontec's Chameleon Programmer. The new version available from
2832 the website uses the original Wiggler layout ('@var{wiggler}')
2833 @item @b{triton} The parallel port adapter found on the
2834 ``Karo Triton 1 Development Board''.
2835 This is also the layout used by the HollyGates design
2836 (see @uref{http://www.lartmaker.nl/projects/jtag/}).
2837 @item @b{wiggler} The original Wiggler layout, also supported by
2838 several clones, such as the Olimex ARM-JTAG
2839 @item @b{wiggler2} Same as original wiggler except an led is fitted on D5.
2840 @item @b{wiggler_ntrst_inverted} Same as original wiggler except TRST is inverted.
2841 @end itemize
2842 @end deffn
2843
2844 @deffn {Config Command} {parport_port} [port_number]
2845 Display either the address of the I/O port
2846 (default: 0x378 for LPT1) or the number of the @file{/dev/parport} device.
2847 If a parameter is provided, first switch to use that port.
2848 This is a write-once setting.
2849
2850 When using PPDEV to access the parallel port, use the number of the parallel port:
2851 @option{parport_port 0} (the default). If @option{parport_port 0x378} is specified
2852 you may encounter a problem.
2853 @end deffn
2854
2855 @deffn Command {parport_toggling_time} [nanoseconds]
2856 Displays how many nanoseconds the hardware needs to toggle TCK;
2857 the parport driver uses this value to obey the
2858 @command{adapter_khz} configuration.
2859 When the optional @var{nanoseconds} parameter is given,
2860 that setting is changed before displaying the current value.
2861
2862 The default setting should work reasonably well on commodity PC hardware.
2863 However, you may want to calibrate for your specific hardware.
2864 @quotation Tip
2865 To measure the toggling time with a logic analyzer or a digital storage
2866 oscilloscope, follow the procedure below:
2867 @example
2868 > parport_toggling_time 1000
2869 > adapter_khz 500
2870 @end example
2871 This sets the maximum JTAG clock speed of the hardware, but
2872 the actual speed probably deviates from the requested 500 kHz.
2873 Now, measure the time between the two closest spaced TCK transitions.
2874 You can use @command{runtest 1000} or something similar to generate a
2875 large set of samples.
2876 Update the setting to match your measurement:
2877 @example
2878 > parport_toggling_time <measured nanoseconds>
2879 @end example
2880 Now the clock speed will be a better match for @command{adapter_khz rate}
2881 commands given in OpenOCD scripts and event handlers.
2882
2883 You can do something similar with many digital multimeters, but note
2884 that you'll probably need to run the clock continuously for several
2885 seconds before it decides what clock rate to show. Adjust the
2886 toggling time up or down until the measured clock rate is a good
2887 match for the adapter_khz rate you specified; be conservative.
2888 @end quotation
2889 @end deffn
2890
2891 @deffn {Config Command} {parport_write_on_exit} (@option{on}|@option{off})
2892 This will configure the parallel driver to write a known
2893 cable-specific value to the parallel interface on exiting OpenOCD.
2894 @end deffn
2895
2896 For example, the interface configuration file for a
2897 classic ``Wiggler'' cable on LPT2 might look something like this:
2898
2899 @example
2900 interface parport
2901 parport_port 0x278
2902 parport_cable wiggler
2903 @end example
2904 @end deffn
2905
2906 @deffn {Interface Driver} {presto}
2907 ASIX PRESTO USB JTAG programmer.
2908 @deffn {Config Command} {presto_serial} serial_string
2909 Configures the USB serial number of the Presto device to use.
2910 @end deffn
2911 @end deffn
2912
2913 @deffn {Interface Driver} {rlink}
2914 Raisonance RLink USB adapter
2915 @end deffn
2916
2917 @deffn {Interface Driver} {usbprog}
2918 usbprog is a freely programmable USB adapter.
2919 @end deffn
2920
2921 @deffn {Interface Driver} {vsllink}
2922 vsllink is part of Versaloon which is a versatile USB programmer.
2923
2924 @quotation Note
2925 This defines quite a few driver-specific commands,
2926 which are not currently documented here.
2927 @end quotation
2928 @end deffn
2929
2930 @anchor{hla_interface}
2931 @deffn {Interface Driver} {hla}
2932 This is a driver that supports multiple High Level Adapters.
2933 This type of adapter does not expose some of the lower level api's
2934 that OpenOCD would normally use to access the target.
2935
2936 Currently supported adapters include the ST STLINK and TI ICDI.
2937 STLINK firmware version >= V2.J21.S4 recommended due to issues with earlier
2938 versions of firmware where serial number is reset after first use. Suggest
2939 using ST firmware update utility to upgrade STLINK firmware even if current
2940 version reported is V2.J21.S4.
2941
2942 @deffn {Config Command} {hla_device_desc} description
2943 Currently Not Supported.
2944 @end deffn
2945
2946 @deffn {Config Command} {hla_serial} serial
2947 Specifies the serial number of the adapter.
2948 @end deffn
2949
2950 @deffn {Config Command} {hla_layout} (@option{stlink}|@option{icdi})
2951 Specifies the adapter layout to use.
2952 @end deffn
2953
2954 @deffn {Config Command} {hla_vid_pid} [vid pid]+
2955 Pairs of vendor IDs and product IDs of the device.
2956 @end deffn
2957
2958 @deffn {Command} {hla_command} command
2959 Execute a custom adapter-specific command. The @var{command} string is
2960 passed as is to the underlying adapter layout handler.
2961 @end deffn
2962 @end deffn
2963
2964 @deffn {Interface Driver} {opendous}
2965 opendous-jtag is a freely programmable USB adapter.
2966 @end deffn
2967
2968 @deffn {Interface Driver} {ulink}
2969 This is the Keil ULINK v1 JTAG debugger.
2970 @end deffn
2971
2972 @deffn {Interface Driver} {ZY1000}
2973 This is the Zylin ZY1000 JTAG debugger.
2974 @end deffn
2975
2976 @quotation Note
2977 This defines some driver-specific commands,
2978 which are not currently documented here.
2979 @end quotation
2980
2981 @deffn Command power [@option{on}|@option{off}]
2982 Turn power switch to target on/off.
2983 No arguments: print status.
2984 @end deffn
2985
2986 @deffn {Interface Driver} {bcm2835gpio}
2987 This SoC is present in Raspberry Pi which is a cheap single-board computer
2988 exposing some GPIOs on its expansion header.
2989
2990 The driver accesses memory-mapped GPIO peripheral registers directly
2991 for maximum performance, but the only possible race condition is for
2992 the pins' modes/muxing (which is highly unlikely), so it should be
2993 able to coexist nicely with both sysfs bitbanging and various
2994 peripherals' kernel drivers. The driver restores the previous
2995 configuration on exit.
2996
2997 See @file{interface/raspberrypi-native.cfg} for a sample config and
2998 pinout.
2999
3000 @end deffn
3001
3002 @deffn {Interface Driver} {imx_gpio}
3003 i.MX SoC is present in many community boards. Wandboard is an example
3004 of the one which is most popular.
3005
3006 This driver is mostly the same as bcm2835gpio.
3007
3008 See @file{interface/imx-native.cfg} for a sample config and
3009 pinout.
3010
3011 @end deffn
3012
3013
3014 @deffn {Interface Driver} {openjtag}
3015 OpenJTAG compatible USB adapter.
3016 This defines some driver-specific commands:
3017
3018 @deffn {Config Command} {openjtag_variant} variant
3019 Specifies the variant of the OpenJTAG adapter (see @uref{http://www.openjtag.org/}).
3020 Currently valid @var{variant} values include:
3021
3022 @itemize @minus
3023 @item @b{standard} Standard variant (default).
3024 @item @b{cy7c65215} Cypress CY7C65215 Dual Channel USB-Serial Bridge Controller
3025 (see @uref{http://www.cypress.com/?rID=82870}).
3026 @end itemize
3027 @end deffn
3028
3029 @deffn {Config Command} {openjtag_device_desc} string
3030 The USB device description string of the adapter.
3031 This value is only used with the standard variant.
3032 @end deffn
3033 @end deffn
3034
3035 @section Transport Configuration
3036 @cindex Transport
3037 As noted earlier, depending on the version of OpenOCD you use,
3038 and the debug adapter you are using,
3039 several transports may be available to
3040 communicate with debug targets (or perhaps to program flash memory).
3041 @deffn Command {transport list}
3042 displays the names of the transports supported by this
3043 version of OpenOCD.
3044 @end deffn
3045
3046 @deffn Command {transport select} @option{transport_name}
3047 Select which of the supported transports to use in this OpenOCD session.
3048
3049 When invoked with @option{transport_name}, attempts to select the named
3050 transport. The transport must be supported by the debug adapter
3051 hardware and by the version of OpenOCD you are using (including the
3052 adapter's driver).
3053
3054 If no transport has been selected and no @option{transport_name} is
3055 provided, @command{transport select} auto-selects the first transport
3056 supported by the debug adapter.
3057
3058 @command{transport select} always returns the name of the session's selected
3059 transport, if any.
3060 @end deffn
3061
3062 @subsection JTAG Transport
3063 @cindex JTAG
3064 JTAG is the original transport supported by OpenOCD, and most
3065 of the OpenOCD commands support it.
3066 JTAG transports expose a chain of one or more Test Access Points (TAPs),
3067 each of which must be explicitly declared.
3068 JTAG supports both debugging and boundary scan testing.
3069 Flash programming support is built on top of debug support.
3070
3071 JTAG transport is selected with the command @command{transport select
3072 jtag}. Unless your adapter uses @ref{hla_interface,the hla interface
3073 driver}, in which case the command is @command{transport select
3074 hla_jtag}.
3075
3076 @subsection SWD Transport
3077 @cindex SWD
3078 @cindex Serial Wire Debug
3079 SWD (Serial Wire Debug) is an ARM-specific transport which exposes one
3080 Debug Access Point (DAP, which must be explicitly declared.
3081 (SWD uses fewer signal wires than JTAG.)
3082 SWD is debug-oriented, and does not support boundary scan testing.
3083 Flash programming support is built on top of debug support.
3084 (Some processors support both JTAG and SWD.)
3085
3086 SWD transport is selected with the command @command{transport select
3087 swd}. Unless your adapter uses @ref{hla_interface,the hla interface
3088 driver}, in which case the command is @command{transport select
3089 hla_swd}.
3090
3091 @deffn Command {swd newdap} ...
3092 Declares a single DAP which uses SWD transport.
3093 Parameters are currently the same as "jtag newtap" but this is
3094 expected to change.
3095 @end deffn
3096 @deffn Command {swd wcr trn prescale}
3097 Updates TRN (turnaraound delay) and prescaling.fields of the
3098 Wire Control Register (WCR).
3099 No parameters: displays current settings.
3100 @end deffn
3101
3102 @subsection SPI Transport
3103 @cindex SPI
3104 @cindex Serial Peripheral Interface
3105 The Serial Peripheral Interface (SPI) is a general purpose transport
3106 which uses four wire signaling. Some processors use it as part of a
3107 solution for flash programming.
3108
3109 @anchor{jtagspeed}
3110 @section JTAG Speed
3111 JTAG clock setup is part of system setup.
3112 It @emph{does not belong with interface setup} since any interface
3113 only knows a few of the constraints for the JTAG clock speed.
3114 Sometimes the JTAG speed is
3115 changed during the target initialization process: (1) slow at
3116 reset, (2) program the CPU clocks, (3) run fast.
3117 Both the "slow" and "fast" clock rates are functions of the
3118 oscillators used, the chip, the board design, and sometimes
3119 power management software that may be active.
3120
3121 The speed used during reset, and the scan chain verification which
3122 follows reset, can be adjusted using a @code{reset-start}
3123 target event handler.
3124 It can then be reconfigured to a faster speed by a
3125 @code{reset-init} target event handler after it reprograms those
3126 CPU clocks, or manually (if something else, such as a boot loader,
3127 sets up those clocks).
3128 @xref{targetevents,,Target Events}.
3129 When the initial low JTAG speed is a chip characteristic, perhaps
3130 because of a required oscillator speed, provide such a handler
3131 in the target config file.
3132 When that speed is a function of a board-specific characteristic
3133 such as which speed oscillator is used, it belongs in the board
3134 config file instead.
3135 In both cases it's safest to also set the initial JTAG clock rate
3136 to that same slow speed, so that OpenOCD never starts up using a
3137 clock speed that's faster than the scan chain can support.
3138
3139 @example
3140 jtag_rclk 3000
3141 $_TARGET.cpu configure -event reset-start @{ jtag_rclk 3000 @}
3142 @end example
3143
3144 If your system supports adaptive clocking (RTCK), configuring
3145 JTAG to use that is probably the most robust approach.
3146 However, it introduces delays to synchronize clocks; so it
3147 may not be the fastest solution.
3148
3149 @b{NOTE:} Script writers should consider using @command{jtag_rclk}
3150 instead of @command{adapter_khz}, but only for (ARM) cores and boards
3151 which support adaptive clocking.
3152
3153 @deffn {Command} adapter_khz max_speed_kHz
3154 A non-zero speed is in KHZ. Hence: 3000 is 3mhz.
3155 JTAG interfaces usually support a limited number of
3156 speeds. The speed actually used won't be faster
3157 than the speed specified.
3158
3159 Chip data sheets generally include a top JTAG clock rate.
3160 The actual rate is often a function of a CPU core clock,
3161 and is normally less than that peak rate.
3162 For example, most ARM cores accept at most one sixth of the CPU clock.
3163
3164 Speed 0 (khz) selects RTCK method.
3165 @xref{faqrtck,,FAQ RTCK}.
3166 If your system uses RTCK, you won't need to change the
3167 JTAG clocking after setup.
3168 Not all interfaces, boards, or targets support ``rtck''.
3169 If the interface device can not
3170 support it, an error is returned when you try to use RTCK.
3171 @end deffn
3172
3173 @defun jtag_rclk fallback_speed_kHz
3174 @cindex adaptive clocking
3175 @cindex RTCK
3176 This Tcl proc (defined in @file{startup.tcl}) attempts to enable RTCK/RCLK.
3177 If that fails (maybe the interface, board, or target doesn't
3178 support it), falls back to the specified frequency.
3179 @example
3180 # Fall back to 3mhz if RTCK is not supported
3181 jtag_rclk 3000
3182 @end example
3183 @end defun
3184
3185 @node Reset Configuration
3186 @chapter Reset Configuration
3187 @cindex Reset Configuration
3188
3189 Every system configuration may require a different reset
3190 configuration. This can also be quite confusing.
3191 Resets also interact with @var{reset-init} event handlers,
3192 which do things like setting up clocks and DRAM, and
3193 JTAG clock rates. (@xref{jtagspeed,,JTAG Speed}.)
3194 They can also interact with JTAG routers.
3195 Please see the various board files for examples.
3196
3197 @quotation Note
3198 To maintainers and integrators:
3199 Reset configuration touches several things at once.
3200 Normally the board configuration file
3201 should define it and assume that the JTAG adapter supports
3202 everything that's wired up to the board's JTAG connector.
3203
3204 However, the target configuration file could also make note
3205 of something the silicon vendor has done inside the chip,
3206 which will be true for most (or all) boards using that chip.
3207 And when the JTAG adapter doesn't support everything, the
3208 user configuration file will need to override parts of
3209 the reset configuration provided by other files.
3210 @end quotation
3211
3212 @section Types of Reset
3213
3214 There are many kinds of reset possible through JTAG, but
3215 they may not all work with a given board and adapter.
3216 That's part of why reset configuration can be error prone.
3217
3218 @itemize @bullet
3219 @item
3220 @emph{System Reset} ... the @emph{SRST} hardware signal
3221 resets all chips connected to the JTAG adapter, such as processors,
3222 power management chips, and I/O controllers. Normally resets triggered
3223 with this signal behave exactly like pressing a RESET button.
3224 @item
3225 @emph{JTAG TAP Reset} ... the @emph{TRST} hardware signal resets
3226 just the TAP controllers connected to the JTAG adapter.
3227 Such resets should not be visible to the rest of the system; resetting a
3228 device's TAP controller just puts that controller into a known state.
3229 @item
3230 @emph{Emulation Reset} ... many devices can be reset through JTAG
3231 commands. These resets are often distinguishable from system
3232 resets, either explicitly (a "reset reason" register says so)
3233 or implicitly (not all parts of the chip get reset).
3234 @item
3235 @emph{Other Resets} ... system-on-chip devices often support
3236 several other types of reset.
3237 You may need to arrange that a watchdog timer stops
3238 while debugging, preventing a watchdog reset.
3239 There may be individual module resets.
3240 @end itemize
3241
3242 In the best case, OpenOCD can hold SRST, then reset
3243 the TAPs via TRST and send commands through JTAG to halt the
3244 CPU at the reset vector before the 1st instruction is executed.
3245 Then when it finally releases the SRST signal, the system is
3246 halted under debugger control before any code has executed.
3247 This is the behavior required to support the @command{reset halt}
3248 and @command{reset init} commands; after @command{reset init} a
3249 board-specific script might do things like setting up DRAM.
3250 (@xref{resetcommand,,Reset Command}.)
3251
3252 @anchor{srstandtrstissues}
3253 @section SRST and TRST Issues
3254
3255 Because SRST and TRST are hardware signals, they can have a
3256 variety of system-specific constraints. Some of the most
3257 common issues are:
3258
3259 @itemize @bullet
3260
3261 @item @emph{Signal not available} ... Some boards don't wire
3262 SRST or TRST to the JTAG connector. Some JTAG adapters don't
3263 support such signals even if they are wired up.
3264 Use the @command{reset_config} @var{signals} options to say
3265 when either of those signals is not connected.
3266 When SRST is not available, your code might not be able to rely
3267 on controllers having been fully reset during code startup.
3268 Missing TRST is not a problem, since JTAG-level resets can
3269 be triggered using with TMS signaling.
3270
3271 @item @emph{Signals shorted} ... Sometimes a chip, board, or
3272 adapter will connect SRST to TRST, instead of keeping them separate.
3273 Use the @command{reset_config} @var{combination} options to say
3274 when those signals aren't properly independent.
3275
3276 @item @emph{Timing} ... Reset circuitry like a resistor/capacitor
3277 delay circuit, reset supervisor, or on-chip features can extend
3278 the effect of a JTAG adapter's reset for some time after the adapter
3279 stops issuing the reset. For example, there may be chip or board
3280 requirements that all reset pulses last for at least a
3281 certain amount of time; and reset buttons commonly have
3282 hardware debouncing.
3283 Use the @command{adapter_nsrst_delay} and @command{jtag_ntrst_delay}
3284 commands to say when extra delays are needed.
3285
3286 @item @emph{Drive type} ... Reset lines often have a pullup
3287 resistor, letting the JTAG interface treat them as open-drain
3288 signals. But that's not a requirement, so the adapter may need
3289 to use push/pull output drivers.
3290 Also, with weak pullups it may be advisable to drive
3291 signals to both levels (push/pull) to minimize rise times.
3292 Use the @command{reset_config} @var{trst_type} and
3293 @var{srst_type} parameters to say how to drive reset signals.
3294
3295 @item @emph{Special initialization} ... Targets sometimes need
3296 special JTAG initialization sequences to handle chip-specific
3297 issues (not limited to errata).
3298 For example, certain JTAG commands might need to be issued while
3299 the system as a whole is in a reset state (SRST active)
3300 but the JTAG scan chain is usable (TRST inactive).
3301 Many systems treat combined assertion of SRST and TRST as a
3302 trigger for a harder reset than SRST alone.
3303 Such custom reset handling is discussed later in this chapter.
3304 @end itemize
3305
3306 There can also be other issues.
3307 Some devices don't fully conform to the JTAG specifications.
3308 Trivial system-specific differences are common, such as
3309 SRST and TRST using slightly different names.
3310 There are also vendors who distribute key JTAG documentation for
3311 their chips only to developers who have signed a Non-Disclosure
3312 Agreement (NDA).
3313
3314 Sometimes there are chip-specific extensions like a requirement to use
3315 the normally-optional TRST signal (precluding use of JTAG adapters which
3316 don't pass TRST through), or needing extra steps to complete a TAP reset.
3317
3318 In short, SRST and especially TRST handling may be very finicky,
3319 needing to cope with both architecture and board specific constraints.
3320
3321 @section Commands for Handling Resets
3322
3323 @deffn {Command} adapter_nsrst_assert_width milliseconds
3324 Minimum amount of time (in milliseconds) OpenOCD should wait
3325 after asserting nSRST (active-low system reset) before
3326 allowing it to be deasserted.
3327 @end deffn
3328
3329 @deffn {Command} adapter_nsrst_delay milliseconds
3330 How long (in milliseconds) OpenOCD should wait after deasserting
3331 nSRST (active-low system reset) before starting new JTAG operations.
3332 When a board has a reset button connected to SRST line it will
3333 probably have hardware debouncing, implying you should use this.
3334 @end deffn
3335
3336 @deffn {Command} jtag_ntrst_assert_width milliseconds
3337 Minimum amount of time (in milliseconds) OpenOCD should wait
3338 after asserting nTRST (active-low JTAG TAP reset) before
3339 allowing it to be deasserted.
3340 @end deffn
3341
3342 @deffn {Command} jtag_ntrst_delay milliseconds
3343 How long (in milliseconds) OpenOCD should wait after deasserting
3344 nTRST (active-low JTAG TAP reset) before starting new JTAG operations.
3345 @end deffn
3346
3347 @deffn {Command} reset_config mode_flag ...
3348 This command displays or modifies the reset configuration
3349 of your combination of JTAG board and target in target
3350 configuration scripts.
3351
3352 Information earlier in this section describes the kind of problems
3353 the command is intended to address (@pxref{srstandtrstissues,,SRST and TRST Issues}).
3354 As a rule this command belongs only in board config files,
3355 describing issues like @emph{board doesn't connect TRST};
3356 or in user config files, addressing limitations derived
3357 from a particular combination of interface and board.
3358 (An unlikely example would be using a TRST-only adapter
3359 with a board that only wires up SRST.)
3360
3361 The @var{mode_flag} options can be specified in any order, but only one
3362 of each type -- @var{signals}, @var{combination}, @var{gates},
3363 @var{trst_type}, @var{srst_type} and @var{connect_type}
3364 -- may be specified at a time.
3365 If you don't provide a new value for a given type, its previous
3366 value (perhaps the default) is unchanged.
3367 For example, this means that you don't need to say anything at all about
3368 TRST just to declare that if the JTAG adapter should want to drive SRST,
3369 it must explicitly be driven high (@option{srst_push_pull}).
3370
3371 @itemize
3372 @item
3373 @var{signals} can specify which of the reset signals are connected.
3374 For example, If the JTAG interface provides SRST, but the board doesn't
3375 connect that signal properly, then OpenOCD can't use it.
3376 Possible values are @option{none} (the default), @option{trst_only},
3377 @option{srst_only} and @option{trst_and_srst}.
3378
3379 @quotation Tip
3380 If your board provides SRST and/or TRST through the JTAG connector,
3381 you must declare that so those signals can be used.
3382 @end quotation
3383
3384 @item
3385 The @var{combination} is an optional value specifying broken reset
3386 signal implementations.
3387 The default behaviour if no option given is @option{separate},
3388 indicating everything behaves normally.
3389 @option{srst_pulls_trst} states that the
3390 test logic is reset together with the reset of the system (e.g. NXP
3391 LPC2000, "broken" board layout), @option{trst_pulls_srst} says that
3392 the system is reset together with the test logic (only hypothetical, I
3393 haven't seen hardware with such a bug, and can be worked around).
3394 @option{combined} implies both @option{srst_pulls_trst} and
3395 @option{trst_pulls_srst}.
3396
3397 @item
3398 The @var{gates} tokens control flags that describe some cases where
3399 JTAG may be unvailable during reset.
3400 @option{srst_gates_jtag} (default)
3401 indicates that asserting SRST gates the
3402 JTAG clock. This means that no communication can happen on JTAG
3403 while SRST is asserted.
3404 Its converse is @option{srst_nogate}, indicating that JTAG commands
3405 can safely be issued while SRST is active.
3406
3407 @item
3408 The @var{connect_type} tokens control flags that describe some cases where
3409 SRST is asserted while connecting to the target. @option{srst_nogate}
3410 is required to use this option.
3411 @option{connect_deassert_srst} (default)
3412 indicates that SRST will not be asserted while connecting to the target.
3413 Its converse is @option{connect_assert_srst}, indicating that SRST will
3414 be asserted before any target connection.
3415 Only some targets support this feature, STM32 and STR9 are examples.
3416 This feature is useful if you are unable to connect to your target due
3417 to incorrect options byte config or illegal program execution.
3418 @end itemize
3419
3420 The optional @var{trst_type} and @var{srst_type} parameters allow the
3421 driver mode of each reset line to be specified. These values only affect
3422 JTAG interfaces with support for different driver modes, like the Amontec
3423 JTAGkey and JTAG Accelerator. Also, they are necessarily ignored if the
3424 relevant signal (TRST or SRST) is not connected.
3425
3426 @itemize
3427 @item
3428 Possible @var{trst_type} driver modes for the test reset signal (TRST)
3429 are the default @option{trst_push_pull}, and @option{trst_open_drain}.
3430 Most boards connect this signal to a pulldown, so the JTAG TAPs
3431 never leave reset unless they are hooked up to a JTAG adapter.
3432
3433 @item
3434 Possible @var{srst_type} driver modes for the system reset signal (SRST)
3435 are the default @option{srst_open_drain}, and @option{srst_push_pull}.
3436 Most boards connect this signal to a pullup, and allow the
3437 signal to be pulled low by various events including system
3438 powerup and pressing a reset button.
3439 @end itemize
3440 @end deffn
3441
3442 @section Custom Reset Handling
3443 @cindex events
3444
3445 OpenOCD has several ways to help support the various reset
3446 mechanisms provided by chip and board vendors.
3447 The commands shown in the previous section give standard parameters.
3448 There are also @emph{event handlers} associated with TAPs or Targets.
3449 Those handlers are Tcl procedures you can provide, which are invoked
3450 at particular points in the reset sequence.
3451
3452 @emph{When SRST is not an option} you must set
3453 up a @code{reset-assert} event handler for your target.
3454 For example, some JTAG adapters don't include the SRST signal;
3455 and some boards have multiple targets, and you won't always
3456 want to reset everything at once.
3457
3458 After configuring those mechanisms, you might still
3459 find your board doesn't start up or reset correctly.
3460 For example, maybe it needs a slightly different sequence
3461 of SRST and/or TRST manipulations, because of quirks that
3462 the @command{reset_config} mechanism doesn't address;
3463 or asserting both might trigger a stronger reset, which
3464 needs special attention.
3465
3466 Experiment with lower level operations, such as @command{jtag_reset}
3467 and the @command{jtag arp_*} operations shown here,
3468 to find a sequence of operations that works.
3469 @xref{JTAG Commands}.
3470 When you find a working sequence, it can be used to override
3471 @command{jtag_init}, which fires during OpenOCD startup
3472 (@pxref{configurationstage,,Configuration Stage});
3473 or @command{init_reset}, which fires during reset processing.
3474
3475 You might also want to provide some project-specific reset
3476 schemes. For example, on a multi-target board the standard
3477 @command{reset} command would reset all targets, but you
3478 may need the ability to reset only one target at time and
3479 thus want to avoid using the board-wide SRST signal.
3480
3481 @deffn {Overridable Procedure} init_reset mode
3482 This is invoked near the beginning of the @command{reset} command,
3483 usually to provide as much of a cold (power-up) reset as practical.
3484 By default it is also invoked from @command{jtag_init} if
3485 the scan chain does not respond to pure JTAG operations.
3486 The @var{mode} parameter is the parameter given to the
3487 low level reset command (@option{halt},
3488 @option{init}, or @option{run}), @option{setup},
3489 or potentially some other value.
3490
3491 The default implementation just invokes @command{jtag arp_init-reset}.
3492 Replacements will normally build on low level JTAG
3493 operations such as @command{jtag_reset}.
3494 Operations here must not address individual TAPs
3495 (or their associated targets)
3496 until the JTAG scan chain has first been verified to work.
3497
3498 Implementations must have verified the JTAG scan chain before
3499 they return.
3500 This is done by calling @command{jtag arp_init}
3501 (or @command{jtag arp_init-reset}).
3502 @end deffn
3503
3504 @deffn Command {jtag arp_init}
3505 This validates the scan chain using just the four
3506 standard JTAG signals (TMS, TCK, TDI, TDO).
3507 It starts by issuing a JTAG-only reset.
3508 Then it performs checks to verify that the scan chain configuration
3509 matches the TAPs it can observe.
3510 Those checks include checking IDCODE values for each active TAP,
3511 and verifying the length of their instruction registers using
3512 TAP @code{-ircapture} and @code{-irmask} values.
3513 If these tests all pass, TAP @code{setup} events are
3514 issued to all TAPs with handlers for that event.
3515 @end deffn
3516
3517 @deffn Command {jtag arp_init-reset}
3518 This uses TRST and SRST to try resetting
3519 everything on the JTAG scan chain
3520 (and anything else connected to SRST).
3521 It then invokes the logic of @command{jtag arp_init}.
3522 @end deffn
3523
3524
3525 @node TAP Declaration
3526 @chapter TAP Declaration
3527 @cindex TAP declaration
3528 @cindex TAP configuration
3529
3530 @emph{Test Access Ports} (TAPs) are the core of JTAG.
3531 TAPs serve many roles, including:
3532
3533 @itemize @bullet
3534 @item @b{Debug Target} A CPU TAP can be used as a GDB debug target.
3535 @item @b{Flash Programming} Some chips program the flash directly via JTAG.
3536 Others do it indirectly, making a CPU do it.
3537 @item @b{Program Download} Using the same CPU support GDB uses,
3538 you can initialize a DRAM controller, download code to DRAM, and then
3539 start running that code.
3540 @item @b{Boundary Scan} Most chips support boundary scan, which
3541 helps test for board assembly problems like solder bridges
3542 and missing connections.
3543 @end itemize
3544
3545 OpenOCD must know about the active TAPs on your board(s).
3546 Setting up the TAPs is the core task of your configuration files.
3547 Once those TAPs are set up, you can pass their names to code
3548 which sets up CPUs and exports them as GDB targets,
3549 probes flash memory, performs low-level JTAG operations, and more.
3550
3551 @section Scan Chains
3552 @cindex scan chain
3553
3554 TAPs are part of a hardware @dfn{scan chain},
3555 which is a daisy chain of TAPs.
3556 They also need to be added to
3557 OpenOCD's software mirror of that hardware list,
3558 giving each member a name and associating other data with it.
3559 Simple scan chains, with a single TAP, are common in
3560 systems with a single microcontroller or microprocessor.
3561 More complex chips may have several TAPs internally.
3562 Very complex scan chains might have a dozen or more TAPs:
3563 several in one chip, more in the next, and connecting
3564 to other boards with their own chips and TAPs.
3565
3566 You can display the list with the @command{scan_chain} command.
3567 (Don't confuse this with the list displayed by the @command{targets}
3568 command, presented in the next chapter.
3569 That only displays TAPs for CPUs which are configured as
3570 debugging targets.)
3571 Here's what the scan chain might look like for a chip more than one TAP:
3572
3573 @verbatim
3574 TapName Enabled IdCode Expected IrLen IrCap IrMask
3575 -- ------------------ ------- ---------- ---------- ----- ----- ------
3576 0 omap5912.dsp Y 0x03df1d81 0x03df1d81 38 0x01 0x03
3577 1 omap5912.arm Y 0x0692602f 0x0692602f 4 0x01 0x0f
3578 2 omap5912.unknown Y 0x00000000 0x00000000 8 0x01 0x03
3579 @end verbatim
3580
3581 OpenOCD can detect some of that information, but not all
3582 of it. @xref{autoprobing,,Autoprobing}.
3583 Unfortunately, those TAPs can't always be autoconfigured,
3584 because not all devices provide good support for that.
3585 JTAG doesn't require supporting IDCODE instructions, and
3586 chips with JTAG routers may not link TAPs into the chain
3587 until they are told to do so.
3588
3589 The configuration mechanism currently supported by OpenOCD
3590 requires explicit configuration of all TAP devices using
3591 @command{jtag newtap} commands, as detailed later in this chapter.
3592 A command like this would declare one tap and name it @code{chip1.cpu}:
3593
3594 @example
3595 jtag newtap chip1 cpu -irlen 4 -expected-id 0x3ba00477
3596 @end example
3597
3598 Each target configuration file lists the TAPs provided
3599 by a given chip.
3600 Board configuration files combine all the targets on a board,
3601 and so forth.
3602 Note that @emph{the order in which TAPs are declared is very important.}
3603 That declaration order must match the order in the JTAG scan chain,
3604 both inside a single chip and between them.
3605 @xref{faqtaporder,,FAQ TAP Order}.
3606
3607 For example, the ST Microsystems STR912 chip has
3608 three separate TAPs@footnote{See the ST
3609 document titled: @emph{STR91xFAxxx, Section 3.15 Jtag Interface, Page:
3610 28/102, Figure 3: JTAG chaining inside the STR91xFA}.
3611 @url{http://eu.st.com/stonline/products/literature/ds/13495.pdf}}.
3612 To configure those taps, @file{target/str912.cfg}
3613 includes commands something like this:
3614
3615 @example
3616 jtag newtap str912 flash ... params ...
3617 jtag newtap str912 cpu ... params ...
3618 jtag newtap str912 bs ... params ...
3619 @end example
3620
3621 Actual config files typically use a variable such as @code{$_CHIPNAME}
3622 instead of literals like @option{str912}, to support more than one chip
3623 of each type. @xref{Config File Guidelines}.
3624
3625 @deffn Command {jtag names}
3626 Returns the names of all current TAPs in the scan chain.
3627 Use @command{jtag cget} or @command{jtag tapisenabled}
3628 to examine attributes and state of each TAP.
3629 @example
3630 foreach t [jtag names] @{
3631 puts [format "TAP: %s\n" $t]
3632 @}
3633 @end example
3634 @end deffn
3635
3636 @deffn Command {scan_chain}
3637 Displays the TAPs in the scan chain configuration,
3638 and their status.
3639 The set of TAPs listed by this command is fixed by
3640 exiting the OpenOCD configuration stage,
3641 but systems with a JTAG router can
3642 enable or disable TAPs dynamically.
3643 @end deffn
3644
3645 @c FIXME! "jtag cget" should be able to return all TAP
3646 @c attributes, like "$target_name cget" does for targets.
3647
3648 @c Probably want "jtag eventlist", and a "tap-reset" event
3649 @c (on entry to RESET state).
3650
3651 @section TAP Names
3652 @cindex dotted name
3653
3654 When TAP objects are declared with @command{jtag newtap},
3655 a @dfn{dotted.name} is created for the TAP, combining the
3656 name of a module (usually a chip) and a label for the TAP.
3657 For example: @code{xilinx.tap}, @code{str912.flash},
3658 @code{omap3530.jrc}, @code{dm6446.dsp}, or @code{stm32.cpu}.
3659 Many other commands use that dotted.name to manipulate or
3660 refer to the TAP. For example, CPU configuration uses the
3661 name, as does declaration of NAND or NOR flash banks.
3662
3663 The components of a dotted name should follow ``C'' symbol
3664 name rules: start with an alphabetic character, then numbers
3665 and underscores are OK; while others (including dots!) are not.
3666
3667 @section TAP Declaration Commands
3668
3669 @c shouldn't this be(come) a {Config Command}?
3670 @deffn Command {jtag newtap} chipname tapname configparams...
3671 Declares a new TAP with the dotted name @var{chipname}.@var{tapname},
3672 and configured according to the various @var{configparams}.
3673
3674 The @var{chipname} is a symbolic name for the chip.
3675 Conventionally target config files use @code{$_CHIPNAME},
3676 defaulting to the model name given by the chip vendor but
3677 overridable.
3678
3679 @cindex TAP naming convention
3680 The @var{tapname} reflects the role of that TAP,
3681 and should follow this convention:
3682
3683 @itemize @bullet
3684 @item @code{bs} -- For boundary scan if this is a separate TAP;
3685 @item @code{cpu} -- The main CPU of the chip, alternatively
3686 @code{arm} and @code{dsp} on chips with both ARM and DSP CPUs,
3687 @code{arm1} and @code{arm2} on chips with two ARMs, and so forth;
3688 @item @code{etb} -- For an embedded trace buffer (example: an ARM ETB11);
3689 @item @code{flash} -- If the chip has a flash TAP, like the str912;
3690 @item @code{jrc} -- For JTAG route controller (example: the ICEPick modules
3691 on many Texas Instruments chips, like the OMAP3530 on Beagleboards);
3692 @item @code{tap} -- Should be used only for FPGA- or CPLD-like devices
3693 with a single TAP;
3694 @item @code{unknownN} -- If you have no idea what the TAP is for (N is a number);
3695 @item @emph{when in doubt} -- Use the chip maker's name in their data sheet.
3696 For example, the Freescale i.MX31 has a SDMA (Smart DMA) with
3697 a JTAG TAP; that TAP should be named @code{sdma}.
3698 @end itemize
3699
3700 Every TAP requires at least the following @var{configparams}:
3701
3702 @itemize @bullet
3703 @item @code{-irlen} @var{NUMBER}
3704 @*The length in bits of the
3705 instruction register, such as 4 or 5 bits.
3706 @end itemize
3707
3708 A TAP may also provide optional @var{configparams}:
3709
3710 @itemize @bullet
3711 @item @code{-disable} (or @code{-enable})
3712 @*Use the @code{-disable} parameter to flag a TAP which is not
3713 linked into the scan chain after a reset using either TRST
3714 or the JTAG state machine's @sc{reset} state.
3715 You may use @code{-enable} to highlight the default state
3716 (the TAP is linked in).
3717 @xref{enablinganddisablingtaps,,Enabling and Disabling TAPs}.
3718 @item @code{-expected-id} @var{NUMBER}
3719 @*A non-zero @var{number} represents a 32-bit IDCODE
3720 which you expect to find when the scan chain is examined.
3721 These codes are not required by all JTAG devices.
3722 @emph{Repeat the option} as many times as required if more than one
3723 ID code could appear (for example, multiple versions).
3724 Specify @var{number} as zero to suppress warnings about IDCODE
3725 values that were found but not included in the list.
3726
3727 Provide this value if at all possible, since it lets OpenOCD
3728 tell when the scan chain it sees isn't right. These values
3729 are provided in vendors' chip documentation, usually a technical
3730 reference manual. Sometimes you may need to probe the JTAG
3731 hardware to find these values.
3732 @xref{autoprobing,,Autoprobing}.
3733 @item @code{-ignore-version}
3734 @*Specify this to ignore the JTAG version field in the @code{-expected-id}
3735 option. When vendors put out multiple versions of a chip, or use the same
3736 JTAG-level ID for several largely-compatible chips, it may be more practical
3737 to ignore the version field than to update config files to handle all of
3738 the various chip IDs. The version field is defined as bit 28-31 of the IDCODE.
3739 @item @code{-ircapture} @var{NUMBER}
3740 @*The bit pattern loaded by the TAP into the JTAG shift register
3741 on entry to the @sc{ircapture} state, such as 0x01.
3742 JTAG requires the two LSBs of this value to be 01.
3743 By default, @code{-ircapture} and @code{-irmask} are set
3744 up to verify that two-bit value. You may provide
3745 additional bits if you know them, or indicate that
3746 a TAP doesn't conform to the JTAG specification.
3747 @item @code{-irmask} @var{NUMBER}
3748 @*A mask used with @code{-ircapture}
3749 to verify that instruction scans work correctly.
3750 Such scans are not used by OpenOCD except to verify that
3751 there seems to be no problems with JTAG scan chain operations.
3752 @end itemize
3753 @end deffn
3754
3755 @section Other TAP commands
3756
3757 @deffn Command {jtag cget} dotted.name @option{-event} event_name
3758 @deffnx Command {jtag configure} dotted.name @option{-event} event_name handler
3759 At this writing this TAP attribute
3760 mechanism is used only for event handling.
3761 (It is not a direct analogue of the @code{cget}/@code{configure}
3762 mechanism for debugger targets.)
3763 See the next section for information about the available events.
3764
3765 The @code{configure} subcommand assigns an event handler,
3766 a TCL string which is evaluated when the event is triggered.
3767 The @code{cget} subcommand returns that handler.
3768 @end deffn
3769
3770 @section TAP Events
3771 @cindex events
3772 @cindex TAP events
3773
3774 OpenOCD includes two event mechanisms.
3775 The one presented here applies to all JTAG TAPs.
3776 The other applies to debugger targets,
3777 which are associated with certain TAPs.
3778
3779 The TAP events currently defined are:
3780
3781 @itemize @bullet
3782 @item @b{post-reset}
3783 @* The TAP has just completed a JTAG reset.
3784 The tap may still be in the JTAG @sc{reset} state.
3785 Handlers for these events might perform initialization sequences
3786 such as issuing TCK cycles, TMS sequences to ensure
3787 exit from the ARM SWD mode, and more.
3788
3789 Because the scan chain has not yet been verified, handlers for these events
3790 @emph{should not issue commands which scan the JTAG IR or DR registers}
3791 of any particular target.
3792 @b{NOTE:} As this is written (September 2009), nothing prevents such access.
3793 @item @b{setup}
3794 @* The scan chain has been reset and verified.
3795 This handler may enable TAPs as needed.
3796 @item @b{tap-disable}
3797 @* The TAP needs to be disabled. This handler should
3798 implement @command{jtag tapdisable}
3799 by issuing the relevant JTAG commands.
3800 @item @b{tap-enable}
3801 @* The TAP needs to be enabled. This handler should
3802 implement @command{jtag tapenable}
3803 by issuing the relevant JTAG commands.
3804 @end itemize
3805
3806 If you need some action after each JTAG reset which isn't actually
3807 specific to any TAP (since you can't yet trust the scan chain's
3808 contents to be accurate), you might:
3809
3810 @example
3811 jtag configure CHIP.jrc -event post-reset @{
3812 echo "JTAG Reset done"
3813 ... non-scan jtag operations to be done after reset
3814 @}
3815 @end example
3816
3817
3818 @anchor{enablinganddisablingtaps}
3819 @section Enabling and Disabling TAPs
3820 @cindex JTAG Route Controller
3821 @cindex jrc
3822
3823 In some systems, a @dfn{JTAG Route Controller} (JRC)
3824 is used to enable and/or disable specific JTAG TAPs.
3825 Many ARM-based chips from Texas Instruments include
3826 an ``ICEPick'' module, which is a JRC.
3827 Such chips include DaVinci and OMAP3 processors.
3828
3829 A given TAP may not be visible until the JRC has been
3830 told to link it into the scan chain; and if the JRC
3831 has been told to unlink that TAP, it will no longer
3832 be visible.
3833 Such routers address problems that JTAG ``bypass mode''
3834 ignores, such as:
3835
3836 @itemize
3837 @item The scan chain can only go as fast as its slowest TAP.
3838 @item Having many TAPs slows instruction scans, since all
3839 TAPs receive new instructions.
3840 @item TAPs in the scan chain must be powered up, which wastes
3841 power and prevents debugging some power management mechanisms.
3842 @end itemize
3843
3844 The IEEE 1149.1 JTAG standard has no concept of a ``disabled'' tap,
3845 as implied by the existence of JTAG routers.
3846 However, the upcoming IEEE 1149.7 framework (layered on top of JTAG)
3847 does include a kind of JTAG router functionality.
3848
3849 @c (a) currently the event handlers don't seem to be able to
3850 @c fail in a way that could lead to no-change-of-state.
3851
3852 In OpenOCD, tap enabling/disabling is invoked by the Tcl commands
3853 shown below, and is implemented using TAP event handlers.
3854 So for example, when defining a TAP for a CPU connected to
3855 a JTAG router, your @file{target.cfg} file
3856 should define TAP event handlers using
3857 code that looks something like this:
3858
3859 @example
3860 jtag configure CHIP.cpu -event tap-enable @{
3861 ... jtag operations using CHIP.jrc
3862 @}
3863 jtag configure CHIP.cpu -event tap-disable @{
3864 ... jtag operations using CHIP.jrc
3865 @}
3866 @end example
3867
3868 Then you might want that CPU's TAP enabled almost all the time:
3869
3870 @example
3871 jtag configure $CHIP.jrc -event setup "jtag tapenable $CHIP.cpu"
3872 @end example
3873
3874 Note how that particular setup event handler declaration
3875 uses quotes to evaluate @code{$CHIP} when the event is configured.
3876 Using brackets @{ @} would cause it to be evaluated later,
3877 at runtime, when it might have a different value.
3878
3879 @deffn Command {jtag tapdisable} dotted.name
3880 If necessary, disables the tap
3881 by sending it a @option{tap-disable} event.
3882 Returns the string "1" if the tap
3883 specified by @var{dotted.name} is enabled,
3884 and "0" if it is disabled.
3885 @end deffn
3886
3887 @deffn Command {jtag tapenable} dotted.name
3888 If necessary, enables the tap
3889 by sending it a @option{tap-enable} event.
3890 Returns the string "1" if the tap
3891 specified by @var{dotted.name} is enabled,
3892 and "0" if it is disabled.
3893 @end deffn
3894
3895 @deffn Command {jtag tapisenabled} dotted.name
3896 Returns the string "1" if the tap
3897 specified by @var{dotted.name} is enabled,
3898 and "0" if it is disabled.
3899
3900 @quotation Note
3901 Humans will find the @command{scan_chain} command more helpful
3902 for querying the state of the JTAG taps.
3903 @end quotation
3904 @end deffn
3905
3906 @anchor{autoprobing}
3907 @section Autoprobing
3908 @cindex autoprobe
3909 @cindex JTAG autoprobe
3910
3911 TAP configuration is the first thing that needs to be done
3912 after interface and reset configuration. Sometimes it's
3913 hard finding out what TAPs exist, or how they are identified.
3914 Vendor documentation is not always easy to find and use.
3915
3916 To help you get past such problems, OpenOCD has a limited
3917 @emph{autoprobing} ability to look at the scan chain, doing
3918 a @dfn{blind interrogation} and then reporting the TAPs it finds.
3919 To use this mechanism, start the OpenOCD server with only data
3920 that configures your JTAG interface, and arranges to come up
3921 with a slow clock (many devices don't support fast JTAG clocks
3922 right when they come out of reset).
3923
3924 For example, your @file{openocd.cfg} file might have:
3925
3926 @example
3927 source [find interface/olimex-arm-usb-tiny-h.cfg]
3928 reset_config trst_and_srst
3929 jtag_rclk 8
3930 @end example
3931
3932 When you start the server without any TAPs configured, it will
3933 attempt to autoconfigure the TAPs. There are two parts to this:
3934
3935 @enumerate
3936 @item @emph{TAP discovery} ...
3937 After a JTAG reset (sometimes a system reset may be needed too),
3938 each TAP's data registers will hold the contents of either the
3939 IDCODE or BYPASS register.
3940 If JTAG communication is working, OpenOCD will see each TAP,
3941 and report what @option{-expected-id} to use with it.
3942 @item @emph{IR Length discovery} ...
3943 Unfortunately JTAG does not provide a reliable way to find out
3944 the value of the @option{-irlen} parameter to use with a TAP
3945 that is discovered.
3946 If OpenOCD can discover the length of a TAP's instruction
3947 register, it will report it.
3948 Otherwise you may need to consult vendor documentation, such
3949 as chip data sheets or BSDL files.
3950 @end enumerate
3951
3952 In many cases your board will have a simple scan chain with just
3953 a single device. Here's what OpenOCD reported with one board
3954 that's a bit more complex:
3955
3956 @example
3957 clock speed 8 kHz
3958 There are no enabled taps. AUTO PROBING MIGHT NOT WORK!!
3959 AUTO auto0.tap - use "jtag newtap auto0 tap -expected-id 0x2b900f0f ..."
3960 AUTO auto1.tap - use "jtag newtap auto1 tap -expected-id 0x07926001 ..."
3961 AUTO auto2.tap - use "jtag newtap auto2 tap -expected-id 0x0b73b02f ..."
3962 AUTO auto0.tap - use "... -irlen 4"
3963 AUTO auto1.tap - use "... -irlen 4"
3964 AUTO auto2.tap - use "... -irlen 6"
3965 no gdb ports allocated as no target has been specified
3966 @end example
3967
3968 Given that information, you should be able to either find some existing
3969 config files to use, or create your own. If you create your own, you
3970 would configure from the bottom up: first a @file{target.cfg} file
3971 with these TAPs, any targets associated with them, and any on-chip
3972 resources; then a @file{board.cfg} with off-chip resources, clocking,
3973 and so forth.
3974
3975 @node CPU Configuration
3976 @chapter CPU Configuration
3977 @cindex GDB target
3978
3979 This chapter discusses how to set up GDB debug targets for CPUs.
3980 You can also access these targets without GDB
3981 (@pxref{Architecture and Core Commands},
3982 and @ref{targetstatehandling,,Target State handling}) and
3983 through various kinds of NAND and NOR flash commands.
3984 If you have multiple CPUs you can have multiple such targets.
3985
3986 We'll start by looking at how to examine the targets you have,
3987 then look at how to add one more target and how to configure it.
3988
3989 @section Target List
3990 @cindex target, current
3991 @cindex target, list
3992
3993 All targets that have been set up are part of a list,
3994 where each member has a name.
3995 That name should normally be the same as the TAP name.
3996 You can display the list with the @command{targets}
3997 (plural!) command.
3998 This display often has only one CPU; here's what it might
3999 look like with more than one:
4000 @verbatim
4001 TargetName Type Endian TapName State
4002 -- ------------------ ---------- ------ ------------------ ------------
4003 0* at91rm9200.cpu arm920t little at91rm9200.cpu running
4004 1 MyTarget cortex_m little mychip.foo tap-disabled
4005 @end verbatim
4006
4007 One member of that list is the @dfn{current target}, which
4008 is implicitly referenced by many commands.
4009 It's the one marked with a @code{*} near the target name.
4010 In particular, memory addresses often refer to the address
4011 space seen by that current target.
4012 Commands like @command{mdw} (memory display words)
4013 and @command{flash erase_address} (erase NOR flash blocks)
4014 are examples; and there are many more.
4015
4016 Several commands let you examine the list of targets:
4017
4018 @deffn Command {target current}
4019 Returns the name of the current target.
4020 @end deffn
4021
4022 @deffn Command {target names}
4023 Lists the names of all current targets in the list.
4024 @example
4025 foreach t [target names] @{
4026 puts [format "Target: %s\n" $t]
4027 @}
4028 @end example
4029 @end deffn
4030
4031 @c yep, "target list" would have been better.
4032 @c plus maybe "target setdefault".
4033
4034 @deffn Command targets [name]
4035 @emph{Note: the name of this command is plural. Other target
4036 command names are singular.}
4037
4038 With no parameter, this command displays a table of all known
4039 targets in a user friendly form.
4040
4041 With a parameter, this command sets the current target to
4042 the given target with the given @var{name}; this is
4043 only relevant on boards which have more than one target.
4044 @end deffn
4045
4046 @section Target CPU Types
4047 @cindex target type
4048 @cindex CPU type
4049
4050 Each target has a @dfn{CPU type}, as shown in the output of
4051 the @command{targets} command. You need to specify that type
4052 when calling @command{target create}.
4053 The CPU type indicates more than just the instruction set.
4054 It also indicates how that instruction set is implemented,
4055 what kind of debug support it integrates,
4056 whether it has an MMU (and if so, what kind),
4057 what core-specific commands may be available
4058 (@pxref{Architecture and Core Commands}),
4059 and more.
4060
4061 It's easy to see what target types are supported,
4062 since there's a command to list them.
4063
4064 @anchor{targettypes}
4065 @deffn Command {target types}
4066 Lists all supported target types.
4067 At this writing, the supported CPU types are:
4068
4069 @itemize @bullet
4070 @item @code{arm11} -- this is a generation of ARMv6 cores
4071 @item @code{arm720t} -- this is an ARMv4 core with an MMU
4072 @item @code{arm7tdmi} -- this is an ARMv4 core
4073 @item @code{arm920t} -- this is an ARMv4 core with an MMU
4074 @item @code{arm926ejs} -- this is an ARMv5 core with an MMU
4075 @item @code{arm966e} -- this is an ARMv5 core
4076 @item @code{arm9tdmi} -- this is an ARMv4 core
4077 @item @code{avr} -- implements Atmel's 8-bit AVR instruction set.
4078 (Support for this is preliminary and incomplete.)
4079 @item @code{cortex_a} -- this is an ARMv7 core with an MMU
4080 @item @code{cortex_m} -- this is an ARMv7 core, supporting only the
4081 compact Thumb2 instruction set.
4082 @item @code{aarch64} -- this is an ARMv8-A core with an MMU
4083 @item @code{dragonite} -- resembles arm966e
4084 @item @code{dsp563xx} -- implements Freescale's 24-bit DSP.
4085 (Support for this is still incomplete.)
4086 @item @code{fa526} -- resembles arm920 (w/o Thumb)
4087 @item @code{feroceon} -- resembles arm926
4088 @item @code{mips_m4k} -- a MIPS core
4089 @item @code{xscale} -- this is actually an architecture,
4090 not a CPU type. It is based on the ARMv5 architecture.
4091 @item @code{openrisc} -- this is an OpenRISC 1000 core.
4092 The current implementation supports three JTAG TAP cores:
4093 @item @code{ls1_sap} -- this is the SAP on NXP LS102x CPUs,
4094 allowing access to physical memory addresses independently of CPU cores.
4095 @itemize @minus
4096 @item @code{OpenCores TAP} (See: @url{http://opencores.org/project,jtag})
4097 @item @code{Altera Virtual JTAG TAP} (See: @url{http://www.altera.com/literature/ug/ug_virtualjtag.pdf})
4098 @item @code{Xilinx BSCAN_* virtual JTAG interface} (See: @url{http://www.xilinx.com/support/documentation/sw_manuals/xilinx14_2/spartan6_hdl.pdf})
4099 @end itemize
4100 And two debug interfaces cores:
4101 @itemize @minus
4102 @item @code{Advanced debug interface} (See: @url{http://opencores.org/project,adv_debug_sys})
4103 @item @code{SoC Debug Interface} (See: @url{http://opencores.org/project,dbg_interface})
4104 @end itemize
4105 @end itemize
4106 @end deffn
4107
4108 To avoid being confused by the variety of ARM based cores, remember
4109 this key point: @emph{ARM is a technology licencing company}.
4110 (See: @url{http://www.arm.com}.)
4111 The CPU name used by OpenOCD will reflect the CPU design that was
4112 licenced, not a vendor brand which incorporates that design.
4113 Name prefixes like arm7, arm9, arm11, and cortex
4114 reflect design generations;
4115 while names like ARMv4, ARMv5, ARMv6, ARMv7 and ARMv8
4116 reflect an architecture version implemented by a CPU design.
4117
4118 @anchor{targetconfiguration}
4119 @section Target Configuration
4120
4121 Before creating a ``target'', you must have added its TAP to the scan chain.
4122 When you've added that TAP, you will have a @code{dotted.name}
4123 which is used to set up the CPU support.
4124 The chip-specific configuration file will normally configure its CPU(s)
4125 right after it adds all of the chip's TAPs to the scan chain.
4126
4127 Although you can set up a target in one step, it's often clearer if you
4128 use shorter commands and do it in two steps: create it, then configure
4129 optional parts.
4130 All operations on the target after it's created will use a new
4131 command, created as part of target creation.
4132
4133 The two main things to configure after target creation are
4134 a work area, which usually has target-specific defaults even
4135 if the board setup code overrides them later;
4136 and event handlers (@pxref{targetevents,,Target Events}), which tend
4137 to be much more board-specific.
4138 The key steps you use might look something like this
4139
4140 @example
4141 target create MyTarget cortex_m -chain-position mychip.cpu
4142 $MyTarget configure -work-area-phys 0x08000 -work-area-size 8096
4143 $MyTarget configure -event reset-deassert-pre @{ jtag_rclk 5 @}
4144 $MyTarget configure -event reset-init @{ myboard_reinit @}
4145 @end example
4146
4147 You should specify a working area if you can; typically it uses some
4148 on-chip SRAM.
4149 Such a working area can speed up many things, including bulk
4150 writes to target memory;
4151 flash operations like checking to see if memory needs to be erased;
4152 GDB memory checksumming;
4153 and more.
4154
4155 @quotation Warning
4156 On more complex chips, the work area can become
4157 inaccessible when application code
4158 (such as an operating system)
4159 enables or disables the MMU.
4160 For example, the particular MMU context used to acess the virtual
4161 address will probably matter ... and that context might not have
4162 easy access to other addresses needed.
4163 At this writing, OpenOCD doesn't have much MMU intelligence.
4164 @end quotation
4165
4166 It's often very useful to define a @code{reset-init} event handler.
4167 For systems that are normally used with a boot loader,
4168 common tasks include updating clocks and initializing memory
4169 controllers.
4170 That may be needed to let you write the boot loader into flash,
4171 in order to ``de-brick'' your board; or to load programs into
4172 external DDR memory without having run the boot loader.
4173
4174 @deffn Command {target create} target_name type configparams...
4175 This command creates a GDB debug target that refers to a specific JTAG tap.
4176 It enters that target into a list, and creates a new
4177 command (@command{@var{target_name}}) which is used for various
4178 purposes including additional configuration.
4179
4180 @itemize @bullet
4181 @item @var{target_name} ... is the name of the debug target.
4182 By convention this should be the same as the @emph{dotted.name}
4183 of the TAP associated with this target, which must be specified here
4184 using the @code{-chain-position @var{dotted.name}} configparam.
4185
4186 This name is also used to create the target object command,
4187 referred to here as @command{$target_name},
4188 and in other places the target needs to be identified.
4189 @item @var{type} ... specifies the target type. @xref{targettypes,,target types}.
4190 @item @var{configparams} ... all parameters accepted by
4191 @command{$target_name configure} are permitted.
4192 If the target is big-endian, set it here with @code{-endian big}.
4193
4194 You @emph{must} set the @code{-chain-position @var{dotted.name}} here.
4195 @end itemize
4196 @end deffn
4197
4198 @deffn Command {$target_name configure} configparams...
4199 The options accepted by this command may also be
4200 specified as parameters to @command{target create}.
4201 Their values can later be queried one at a time by
4202 using the @command{$target_name cget} command.
4203
4204 @emph{Warning:} changing some of these after setup is dangerous.
4205 For example, moving a target from one TAP to another;
4206 and changing its endianness.
4207
4208 @itemize @bullet
4209
4210 @item @code{-chain-position} @var{dotted.name} -- names the TAP
4211 used to access this target.
4212
4213 @item @code{-endian} (@option{big}|@option{little}) -- specifies
4214 whether the CPU uses big or little endian conventions
4215
4216 @item @code{-event} @var{event_name} @var{event_body} --
4217 @xref{targetevents,,Target Events}.
4218 Note that this updates a list of named event handlers.
4219 Calling this twice with two different event names assigns
4220 two different handlers, but calling it twice with the
4221 same event name assigns only one handler.
4222
4223 Current target is temporarily overridden to the event issuing target
4224 before handler code starts and switched back after handler is done.
4225
4226 @item @code{-work-area-backup} (@option{0}|@option{1}) -- says
4227 whether the work area gets backed up; by default,
4228 @emph{it is not backed up.}
4229 When possible, use a working_area that doesn't need to be backed up,
4230 since performing a backup slows down operations.
4231 For example, the beginning of an SRAM block is likely to
4232 be used by most build systems, but the end is often unused.
4233
4234 @item @code{-work-area-size} @var{size} -- specify work are size,
4235 in bytes. The same size applies regardless of whether its physical
4236 or virtual address is being used.
4237
4238 @item @code{-work-area-phys} @var{address} -- set the work area
4239 base @var{address} to be used when no MMU is active.
4240
4241 @item @code{-work-area-virt} @var{address} -- set the work area
4242 base @var{address} to be used when an MMU is active.
4243 @emph{Do not specify a value for this except on targets with an MMU.}
4244 The value should normally correspond to a static mapping for the
4245 @code{-work-area-phys} address, set up by the current operating system.
4246
4247 @anchor{rtostype}
4248 @item @code{-rtos} @var{rtos_type} -- enable rtos support for target,
4249 @var{rtos_type} can be one of @option{auto}, @option{eCos},
4250 @option{ThreadX}, @option{FreeRTOS}, @option{linux}, @option{ChibiOS},
4251 @option{embKernel}, @option{mqx}, @option{uCOS-III}
4252 @xref{gdbrtossupport,,RTOS Support}.
4253
4254 @item @code{-defer-examine} -- skip target examination at initial JTAG chain
4255 scan and after a reset. A manual call to arp_examine is required to
4256 access the target for debugging.
4257
4258 @item @code{-ap-num} @var{ap_number} -- set DAP access port for target,
4259 @var{ap_number} is the numeric index of the DAP AP the target is connected to.
4260 Use this option with systems where multiple, independent cores are connected
4261 to separate access ports of the same DAP.
4262
4263 @item @code{-ctibase} @var{address} -- set base address of Cross-Trigger interface (CTI) connected
4264 to the target. Currently, only the @code{aarch64} target makes use of this option, where it is
4265 a mandatory configuration for the target run control.
4266 @end itemize
4267 @end deffn
4268
4269 @section Other $target_name Commands
4270 @cindex object command
4271
4272 The Tcl/Tk language has the concept of object commands,
4273 and OpenOCD adopts that same model for targets.
4274
4275 A good Tk example is a on screen button.
4276 Once a button is created a button
4277 has a name (a path in Tk terms) and that name is useable as a first
4278 class command. For example in Tk, one can create a button and later
4279 configure it like this:
4280
4281 @example
4282 # Create
4283 button .foobar -background red -command @{ foo @}
4284 # Modify
4285 .foobar configure -foreground blue
4286 # Query
4287 set x [.foobar cget -background]
4288 # Report
4289 puts [format "The button is %s" $x]
4290 @end example
4291
4292 In OpenOCD's terms, the ``target'' is an object just like a Tcl/Tk
4293 button, and its object commands are invoked the same way.
4294
4295 @example
4296 str912.cpu mww 0x1234 0x42
4297 omap3530.cpu mww 0x5555 123
4298 @end example
4299
4300 The commands supported by OpenOCD target objects are:
4301
4302 @deffn Command {$target_name arp_examine} @option{allow-defer}
4303 @deffnx Command {$target_name arp_halt}
4304 @deffnx Command {$target_name arp_poll}
4305 @deffnx Command {$target_name arp_reset}
4306 @deffnx Command {$target_name arp_waitstate}
4307 Internal OpenOCD scripts (most notably @file{startup.tcl})
4308 use these to deal with specific reset cases.
4309 They are not otherwise documented here.
4310 @end deffn
4311
4312 @deffn Command {$target_name array2mem} arrayname width address count
4313 @deffnx Command {$target_name mem2array} arrayname width address count
4314 These provide an efficient script-oriented interface to memory.
4315 The @code{array2mem} primitive writes bytes, halfwords, or words;
4316 while @code{mem2array} reads them.
4317 In both cases, the TCL side uses an array, and
4318 the target side uses raw memory.
4319
4320 The efficiency comes from enabling the use of
4321 bulk JTAG data transfer operations.
4322 The script orientation comes from working with data
4323 values that are packaged for use by TCL scripts;
4324 @command{mdw} type primitives only print data they retrieve,
4325 and neither store nor return those values.
4326
4327 @itemize
4328 @item @var{arrayname} ... is the name of an array variable
4329 @item @var{width} ... is 8/16/32 - indicating the memory access size
4330 @item @var{address} ... is the target memory address
4331 @item @var{count} ... is the number of elements to process
4332 @end itemize
4333 @end deffn
4334
4335 @deffn Command {$target_name cget} queryparm
4336 Each configuration parameter accepted by
4337 @command{$target_name configure}
4338 can be individually queried, to return its current value.
4339 The @var{queryparm} is a parameter name
4340 accepted by that command, such as @code{-work-area-phys}.
4341 There are a few special cases:
4342
4343 @itemize @bullet
4344 @item @code{-event} @var{event_name} -- returns the handler for the
4345 event named @var{event_name}.
4346 This is a special case because setting a handler requires
4347 two parameters.
4348 @item @code{-type} -- returns the target type.
4349 This is a special case because this is set using
4350 @command{target create} and can't be changed
4351 using @command{$target_name configure}.
4352 @end itemize
4353
4354 For example, if you wanted to summarize information about
4355 all the targets you might use something like this:
4356
4357 @example
4358 foreach name [target names] @{
4359 set y [$name cget -endian]
4360 set z [$name cget -type]
4361 puts [format "Chip %d is %s, Endian: %s, type: %s" \
4362 $x $name $y $z]
4363 @}
4364 @end example
4365 @end deffn
4366
4367 @anchor{targetcurstate}
4368 @deffn Command {$target_name curstate}
4369 Displays the current target state:
4370 @code{debug-running},
4371 @code{halted},
4372 @code{reset},
4373 @code{running}, or @code{unknown}.
4374 (Also, @pxref{eventpolling,,Event Polling}.)
4375 @end deffn
4376
4377 @deffn Command {$target_name eventlist}
4378 Displays a table listing all event handlers
4379 currently associated with this target.
4380 @xref{targetevents,,Target Events}.
4381 @end deffn
4382
4383 @deffn Command {$target_name invoke-event} event_name
4384 Invokes the handler for the event named @var{event_name}.
4385 (This is primarily intended for use by OpenOCD framework
4386 code, for example by the reset code in @file{startup.tcl}.)
4387 @end deffn
4388
4389 @deffn Command {$target_name mdw} addr [count]
4390 @deffnx Command {$target_name mdh} addr [count]
4391 @deffnx Command {$target_name mdb} addr [count]
4392 Display contents of address @var{addr}, as
4393 32-bit words (@command{mdw}), 16-bit halfwords (@command{mdh}),
4394 or 8-bit bytes (@command{mdb}).
4395 If @var{count} is specified, displays that many units.
4396 (If you want to manipulate the data instead of displaying it,
4397 see the @code{mem2array} primitives.)
4398 @end deffn
4399
4400 @deffn Command {$target_name mww} addr word
4401 @deffnx Command {$target_name mwh} addr halfword
4402 @deffnx Command {$target_name mwb} addr byte
4403 Writes the specified @var{word} (32 bits),
4404 @var{halfword} (16 bits), or @var{byte} (8-bit) pattern,
4405 at the specified address @var{addr}.
4406 @end deffn
4407
4408 @anchor{targetevents}
4409 @section Target Events
4410 @cindex target events
4411 @cindex events
4412 At various times, certain things can happen, or you want them to happen.
4413 For example:
4414 @itemize @bullet
4415 @item What should happen when GDB connects? Should your target reset?
4416 @item When GDB tries to flash the target, do you need to enable the flash via a special command?
4417 @item Is using SRST appropriate (and possible) on your system?
4418 Or instead of that, do you need to issue JTAG commands to trigger reset?
4419 SRST usually resets everything on the scan chain, which can be inappropriate.
4420 @item During reset, do you need to write to certain memory locations
4421 to set up system clocks or
4422 to reconfigure the SDRAM?
4423 How about configuring the watchdog timer, or other peripherals,
4424 to stop running while you hold the core stopped for debugging?
4425 @end itemize
4426
4427 All of the above items can be addressed by target event handlers.
4428 These are set up by @command{$target_name configure -event} or
4429 @command{target create ... -event}.
4430
4431 The programmer's model matches the @code{-command} option used in Tcl/Tk
4432 buttons and events. The two examples below act the same, but one creates
4433 and invokes a small procedure while the other inlines it.
4434
4435 @example
4436 proc my_init_proc @{ @} @{
4437 echo "Disabling watchdog..."
4438 mww 0xfffffd44 0x00008000
4439 @}
4440 mychip.cpu configure -event reset-init my_init_proc
4441 mychip.cpu configure -event reset-init @{
4442 echo "Disabling watchdog..."
4443 mww 0xfffffd44 0x00008000
4444 @}
4445 @end example
4446
4447 The following target events are defined:
4448
4449 @itemize @bullet
4450 @item @b{debug-halted}
4451 @* The target has halted for debug reasons (i.e.: breakpoint)
4452 @item @b{debug-resumed}
4453 @* The target has resumed (i.e.: GDB said run)
4454 @item @b{early-halted}
4455 @* Occurs early in the halt process
4456 @item @b{examine-start}
4457 @* Before target examine is called.
4458 @item @b{examine-end}
4459 @* After target examine is called with no errors.
4460 @item @b{gdb-attach}
4461 @* When GDB connects. This is before any communication with the target and GDB
4462 expects the target is halted during attachment.
4463 @xref{gdbmeminspect,,GDB as a non-intrusive memory inspector} for exclusion.
4464 The event can be also used to set up the target so it is possible to probe flash.
4465 Probing flash is necessary during GDB connect if you want to use
4466 @pxref{programmingusinggdb,,programming using GDB}.
4467 Another use of the flash memory map is for GDB to automatically choose
4468 hardware or software breakpoints depending on whether the breakpoint
4469 is in RAM or read only memory.
4470 Default is @code{halt}
4471 @item @b{gdb-detach}
4472 @* When GDB disconnects
4473 @item @b{gdb-end}
4474 @* When the target has halted and GDB is not doing anything (see early halt)
4475 @item @b{gdb-flash-erase-start}
4476 @* Before the GDB flash process tries to erase the flash (default is
4477 @code{reset init})
4478 @item @b{gdb-flash-erase-end}
4479 @* After the GDB flash process has finished erasing the flash
4480 @item @b{gdb-flash-write-start}
4481 @* Before GDB writes to the flash
4482 @item @b{gdb-flash-write-end}
4483 @* After GDB writes to the flash (default is @code{reset halt})
4484 @item @b{gdb-start}
4485 @* Before the target steps, GDB is trying to start/resume the target
4486 @item @b{halted}
4487 @* The target has halted
4488 @item @b{reset-assert-pre}
4489 @* Issued as part of @command{reset} processing
4490 after @command{reset-start} was triggered
4491 but before either SRST alone is asserted on the scan chain,
4492 or @code{reset-assert} is triggered.
4493 @item @b{reset-assert}
4494 @* Issued as part of @command{reset} processing
4495 after @command{reset-assert-pre} was triggered.
4496 When such a handler is present, cores which support this event will use
4497 it instead of asserting SRST.
4498 This support is essential for debugging with JTAG interfaces which
4499 don't include an SRST line (JTAG doesn't require SRST), and for
4500 selective reset on scan chains that have multiple targets.
4501 @item @b{reset-assert-post}
4502 @* Issued as part of @command{reset} processing
4503 after @code{reset-assert} has been triggered.
4504 or the target asserted SRST on the entire scan chain.
4505 @item @b{reset-deassert-pre}
4506 @* Issued as part of @command{reset} processing
4507 after @code{reset-assert-post} has been triggered.
4508 @item @b{reset-deassert-post}
4509 @* Issued as part of @command{reset} processing
4510 after @code{reset-deassert-pre} has been triggered
4511 and (if the target is using it) after SRST has been
4512 released on the scan chain.
4513 @item @b{reset-end}
4514 @* Issued as the final step in @command{reset} processing.
4515 @item @b{reset-init}
4516 @* Used by @b{reset init} command for board-specific initialization.
4517 This event fires after @emph{reset-deassert-post}.
4518
4519 This is where you would configure PLLs and clocking, set up DRAM so
4520 you can download programs that don't fit in on-chip SRAM, set up pin
4521 multiplexing, and so on.
4522 (You may be able to switch to a fast JTAG clock rate here, after
4523 the target clocks are fully set up.)
4524 @item @b{reset-start}
4525 @* Issued as the first step in @command{reset} processing
4526 before @command{reset-assert-pre} is called.
4527
4528 This is the most robust place to use @command{jtag_rclk}
4529 or @command{adapter_khz} to switch to a low JTAG clock rate,
4530 when reset disables PLLs needed to use a fast clock.
4531 @item @b{resume-start}
4532 @* Before any target is resumed
4533 @item @b{resume-end}
4534 @* After all targets have resumed
4535 @item @b{resumed}
4536 @* Target has resumed
4537 @item @b{trace-config}
4538 @* After target hardware trace configuration was changed
4539 @end itemize
4540
4541 @node Flash Commands
4542 @chapter Flash Commands
4543
4544 OpenOCD has different commands for NOR and NAND flash;
4545 the ``flash'' command works with NOR flash, while
4546 the ``nand'' command works with NAND flash.
4547 This partially reflects different hardware technologies:
4548 NOR flash usually supports direct CPU instruction and data bus access,
4549 while data from a NAND flash must be copied to memory before it can be
4550 used. (SPI flash must also be copied to memory before use.)
4551 However, the documentation also uses ``flash'' as a generic term;
4552 for example, ``Put flash configuration in board-specific files''.
4553
4554 Flash Steps:
4555 @enumerate
4556 @item Configure via the command @command{flash bank}
4557 @* Do this in a board-specific configuration file,
4558 passing parameters as needed by the driver.
4559 @item Operate on the flash via @command{flash subcommand}
4560 @* Often commands to manipulate the flash are typed by a human, or run
4561 via a script in some automated way. Common tasks include writing a
4562 boot loader, operating system, or other data.
4563 @item GDB Flashing
4564 @* Flashing via GDB requires the flash be configured via ``flash
4565 bank'', and the GDB flash features be enabled.
4566 @xref{gdbconfiguration,,GDB Configuration}.
4567 @end enumerate
4568
4569 Many CPUs have the ablity to ``boot'' from the first flash bank.
4570 This means that misprogramming that bank can ``brick'' a system,
4571 so that it can't boot.
4572 JTAG tools, like OpenOCD, are often then used to ``de-brick'' the
4573 board by (re)installing working boot firmware.
4574
4575 @anchor{norconfiguration}
4576 @section Flash Configuration Commands
4577 @cindex flash configuration
4578
4579 @deffn {Config Command} {flash bank} name driver base size chip_width bus_width target [driver_options]
4580 Configures a flash bank which provides persistent storage
4581 for addresses from @math{base} to @math{base + size - 1}.
4582 These banks will often be visible to GDB through the target's memory map.
4583 In some cases, configuring a flash bank will activate extra commands;
4584 see the driver-specific documentation.
4585
4586 @itemize @bullet
4587 @item @var{name} ... may be used to reference the flash bank
4588 in other flash commands. A number is also available.
4589 @item @var{driver} ... identifies the controller driver
4590 associated with the flash bank being declared.
4591 This is usually @code{cfi} for external flash, or else
4592 the name of a microcontroller with embedded flash memory.
4593 @xref{flashdriverlist,,Flash Driver List}.
4594 @item @var{base} ... Base address of the flash chip.
4595 @item @var{size} ... Size of the chip, in bytes.
4596 For some drivers, this value is detected from the hardware.
4597 @item @var{chip_width} ... Width of the flash chip, in bytes;
4598 ignored for most microcontroller drivers.
4599 @item @var{bus_width} ... Width of the data bus used to access the
4600 chip, in bytes; ignored for most microcontroller drivers.
4601 @item @var{target} ... Names the target used to issue
4602 commands to the flash controller.
4603 @comment Actually, it's currently a controller-specific parameter...
4604 @item @var{driver_options} ... drivers may support, or require,
4605 additional parameters. See the driver-specific documentation
4606 for more information.
4607 @end itemize
4608 @quotation Note
4609 This command is not available after OpenOCD initialization has completed.
4610 Use it in board specific configuration files, not interactively.
4611 @end quotation
4612 @end deffn
4613
4614 @comment the REAL name for this command is "ocd_flash_banks"
4615 @comment less confusing would be: "flash list" (like "nand list")
4616 @deffn Command {flash banks}
4617 Prints a one-line summary of each device that was
4618 declared using @command{flash bank}, numbered from zero.
4619 Note that this is the @emph{plural} form;
4620 the @emph{singular} form is a very different command.
4621 @end deffn
4622
4623 @deffn Command {flash list}
4624 Retrieves a list of associative arrays for each device that was
4625 declared using @command{flash bank}, numbered from zero.
4626 This returned list can be manipulated easily from within scripts.
4627 @end deffn
4628
4629 @deffn Command {flash probe} num
4630 Identify the flash, or validate the parameters of the configured flash. Operation
4631 depends on the flash type.
4632 The @var{num} parameter is a value shown by @command{flash banks}.
4633 Most flash commands will implicitly @emph{autoprobe} the bank;
4634 flash drivers can distinguish between probing and autoprobing,
4635 but most don't bother.
4636 @end deffn
4637
4638 @section Erasing, Reading, Writing to Flash
4639 @cindex flash erasing
4640 @cindex flash reading
4641 @cindex flash writing
4642 @cindex flash programming
4643 @anchor{flashprogrammingcommands}
4644
4645 One feature distinguishing NOR flash from NAND or serial flash technologies
4646 is that for read access, it acts exactly like any other addressible memory.
4647 This means you can use normal memory read commands like @command{mdw} or
4648 @command{dump_image} with it, with no special @command{flash} subcommands.
4649 @xref{memoryaccess,,Memory access}, and @ref{imageaccess,,Image access}.
4650
4651 Write access works differently. Flash memory normally needs to be erased
4652 before it's written. Erasing a sector turns all of its bits to ones, and
4653 writing can turn ones into zeroes. This is why there are special commands
4654 for interactive erasing and writing, and why GDB needs to know which parts
4655 of the address space hold NOR flash memory.
4656
4657 @quotation Note
4658 Most of these erase and write commands leverage the fact that NOR flash
4659 chips consume target address space. They implicitly refer to the current
4660 JTAG target, and map from an address in that target's address space
4661 back to a flash bank.
4662 @comment In May 2009, those mappings may fail if any bank associated
4663 @comment with that target doesn't succesfuly autoprobe ... bug worth fixing?
4664 A few commands use abstract addressing based on bank and sector numbers,
4665 and don't depend on searching the current target and its address space.
4666 Avoid confusing the two command models.
4667 @end quotation
4668
4669 Some flash chips implement software protection against accidental writes,
4670 since such buggy writes could in some cases ``brick'' a system.
4671 For such systems, erasing and writing may require sector protection to be
4672 disabled first.
4673 Examples include CFI flash such as ``Intel Advanced Bootblock flash'',
4674 and AT91SAM7 on-chip flash.
4675 @xref{flashprotect,,flash protect}.
4676
4677 @deffn Command {flash erase_sector} num first last
4678 Erase sectors in bank @var{num}, starting at sector @var{first}
4679 up to and including @var{last}.
4680 Sector numbering starts at 0.
4681 Providing a @var{last} sector of @option{last}
4682 specifies "to the end of the flash bank".
4683 The @var{num} parameter is a value shown by @command{flash banks}.
4684 @end deffn
4685
4686 @deffn Command {flash erase_address} [@option{pad}] [@option{unlock}] address length
4687 Erase sectors starting at @var{address} for @var{length} bytes.
4688 Unless @option{pad} is specified, @math{address} must begin a
4689 flash sector, and @math{address + length - 1} must end a sector.
4690 Specifying @option{pad} erases extra data at the beginning and/or
4691 end of the specified region, as needed to erase only full sectors.
4692 The flash bank to use is inferred from the @var{address}, and
4693 the specified length must stay within that bank.
4694 As a special case, when @var{length} is zero and @var{address} is
4695 the start of the bank, the whole flash is erased.
4696 If @option{unlock} is specified, then the flash is unprotected
4697 before erase starts.
4698 @end deffn
4699
4700 @deffn Command {flash fillw} address word length
4701 @deffnx Command {flash fillh} address halfword length
4702 @deffnx Command {flash fillb} address byte length
4703 Fills flash memory with the specified @var{word} (32 bits),
4704 @var{halfword} (16 bits), or @var{byte} (8-bit) pattern,
4705 starting at @var{address} and continuing
4706 for @var{length} units (word/halfword/byte).
4707 No erasure is done before writing; when needed, that must be done
4708 before issuing this command.
4709 Writes are done in blocks of up to 1024 bytes, and each write is
4710 verified by reading back the data and comparing it to what was written.
4711 The flash bank to use is inferred from the @var{address} of
4712 each block, and the specified length must stay within that bank.
4713 @end deffn
4714 @comment no current checks for errors if fill blocks touch multiple banks!
4715
4716 @deffn Command {flash write_bank} num filename [offset]
4717 Write the binary @file{filename} to flash bank @var{num},
4718 starting at @var{offset} bytes from the beginning of the bank. If @var{offset}
4719 is omitted, start at the beginning of the flash bank.
4720 The @var{num} parameter is a value shown by @command{flash banks}.
4721 @end deffn
4722
4723 @deffn Command {flash read_bank} num filename [offset [length]]
4724 Read @var{length} bytes from the flash bank @var{num} starting at @var{offset}
4725 and write the contents to the binary @file{filename}. If @var{offset} is
4726 omitted, start at the beginning of the flash bank. If @var{length} is omitted,
4727 read the remaining bytes from the flash bank.
4728 The @var{num} parameter is a value shown by @command{flash banks}.
4729 @end deffn
4730
4731 @deffn Command {flash verify_bank} num filename [offset]
4732 Compare the contents of the binary file @var{filename} with the contents of the
4733 flash bank @var{num} starting at @var{offset}. If @var{offset} is omitted,
4734 start at the beginning of the flash bank. Fail if the contents do not match.
4735 The @var{num} parameter is a value shown by @command{flash banks}.
4736 @end deffn
4737
4738 @deffn Command {flash write_image} [erase] [unlock] filename [offset] [type]
4739 Write the image @file{filename} to the current target's flash bank(s).
4740 Only loadable sections from the image are written.
4741 A relocation @var{offset} may be specified, in which case it is added
4742 to the base address for each section in the image.
4743 The file [@var{type}] can be specified
4744 explicitly as @option{bin} (binary), @option{ihex} (Intel hex),
4745 @option{elf} (ELF file), @option{s19} (Motorola s19).
4746 @option{mem}, or @option{builder}.
4747 The relevant flash sectors will be erased prior to programming
4748 if the @option{erase} parameter is given. If @option{unlock} is
4749 provided, then the flash banks are unlocked before erase and
4750 program. The flash bank to use is inferred from the address of
4751 each image section.
4752
4753 @quotation Warning
4754 Be careful using the @option{erase} flag when the flash is holding
4755 data you want to preserve.
4756 Portions of the flash outside those described in the image's
4757 sections might be erased with no notice.
4758 @itemize
4759 @item
4760 When a section of the image being written does not fill out all the
4761 sectors it uses, the unwritten parts of those sectors are necessarily
4762 also erased, because sectors can't be partially erased.
4763 @item
4764 Data stored in sector "holes" between image sections are also affected.
4765 For example, "@command{flash write_image erase ...}" of an image with
4766 one byte at the beginning of a flash bank and one byte at the end
4767 erases the entire bank -- not just the two sectors being written.
4768 @end itemize
4769 Also, when flash protection is important, you must re-apply it after
4770 it has been removed by the @option{unlock} flag.
4771 @end quotation
4772
4773 @end deffn
4774
4775 @section Other Flash commands
4776 @cindex flash protection
4777
4778 @deffn Command {flash erase_check} num
4779 Check erase state of sectors in flash bank @var{num},
4780 and display that status.
4781 The @var{num} parameter is a value shown by @command{flash banks}.
4782 @end deffn
4783
4784 @deffn Command {flash info} num [sectors]
4785 Print info about flash bank @var{num}, a list of protection blocks
4786 and their status. Use @option{sectors} to show a list of sectors instead.
4787
4788 The @var{num} parameter is a value shown by @command{flash banks}.
4789 This command will first query the hardware, it does not print cached
4790 and possibly stale information.
4791 @end deffn
4792
4793 @anchor{flashprotect}
4794 @deffn Command {flash protect} num first last (@option{on}|@option{off})
4795 Enable (@option{on}) or disable (@option{off}) protection of flash blocks
4796 in flash bank @var{num}, starting at protection block @var{first}
4797 and continuing up to and including @var{last}.
4798 Providing a @var{last} block of @option{last}
4799 specifies "to the end of the flash bank".
4800 The @var{num} parameter is a value shown by @command{flash banks}.
4801 The protection block is usually identical to a flash sector.
4802 Some devices may utilize a protection block distinct from flash sector.
4803 See @command{flash info} for a list of protection blocks.
4804 @end deffn
4805
4806 @deffn Command {flash padded_value} num value
4807 Sets the default value used for padding any image sections, This should
4808 normally match the flash bank erased value. If not specified by this
4809 comamnd or the flash driver then it defaults to 0xff.
4810 @end deffn
4811
4812 @anchor{program}
4813 @deffn Command {program} filename [verify] [reset] [exit] [offset]
4814 This is a helper script that simplifies using OpenOCD as a standalone
4815 programmer. The only required parameter is @option{filename}, the others are optional.
4816 @xref{Flash Programming}.
4817 @end deffn
4818
4819 @anchor{flashdriverlist}
4820 @section Flash Driver List
4821 As noted above, the @command{flash bank} command requires a driver name,
4822 and allows driver-specific options and behaviors.
4823 Some drivers also activate driver-specific commands.
4824
4825 @deffn {Flash Driver} virtual
4826 This is a special driver that maps a previously defined bank to another
4827 address. All bank settings will be copied from the master physical bank.
4828
4829 The @var{virtual} driver defines one mandatory parameters,
4830
4831 @itemize
4832 @item @var{master_bank} The bank that this virtual address refers to.
4833 @end itemize
4834
4835 So in the following example addresses 0xbfc00000 and 0x9fc00000 refer to
4836 the flash bank defined at address 0x1fc00000. Any cmds executed on
4837 the virtual banks are actually performed on the physical banks.
4838 @example
4839 flash bank $_FLASHNAME pic32mx 0x1fc00000 0 0 0 $_TARGETNAME
4840 flash bank vbank0 virtual 0xbfc00000 0 0 0 \
4841 $_TARGETNAME $_FLASHNAME
4842 flash bank vbank1 virtual 0x9fc00000 0 0 0 \
4843 $_TARGETNAME $_FLASHNAME
4844 @end example
4845 @end deffn
4846
4847 @subsection External Flash
4848
4849 @deffn {Flash Driver} cfi
4850 @cindex Common Flash Interface
4851 @cindex CFI
4852 The ``Common Flash Interface'' (CFI) is the main standard for
4853 external NOR flash chips, each of which connects to a
4854 specific external chip select on the CPU.
4855 Frequently the first such chip is used to boot the system.
4856 Your board's @code{reset-init} handler might need to
4857 configure additional chip selects using other commands (like: @command{mww} to
4858 configure a bus and its timings), or
4859 perhaps configure a GPIO pin that controls the ``write protect'' pin
4860 on the flash chip.
4861 The CFI driver can use a target-specific working area to significantly
4862 speed up operation.
4863
4864 The CFI driver can accept the following optional parameters, in any order:
4865
4866 @itemize
4867 @item @var{jedec_probe} ... is used to detect certain non-CFI flash ROMs,
4868 like AM29LV010 and similar types.
4869 @item @var{x16_as_x8} ... when a 16-bit flash is hooked up to an 8-bit bus.
4870 @item @var{bus_swap} ... when data bytes in a 16-bit flash needs to be swapped.
4871 @item @var{data_swap} ... when data bytes in a 16-bit flash needs to be
4872 swapped when writing data values (ie. not CFI commands).
4873 @end itemize
4874
4875 To configure two adjacent banks of 16 MBytes each, both sixteen bits (two bytes)
4876 wide on a sixteen bit bus:
4877
4878 @example
4879 flash bank $_FLASHNAME cfi 0x00000000 0x01000000 2 2 $_TARGETNAME
4880 flash bank $_FLASHNAME cfi 0x01000000 0x01000000 2 2 $_TARGETNAME
4881 @end example
4882
4883 To configure one bank of 32 MBytes
4884 built from two sixteen bit (two byte) wide parts wired in parallel
4885 to create a thirty-two bit (four byte) bus with doubled throughput:
4886
4887 @example
4888 flash bank $_FLASHNAME cfi 0x00000000 0x02000000 2 4 $_TARGETNAME
4889 @end example
4890
4891 @c "cfi part_id" disabled
4892 @end deffn
4893
4894 @deffn {Flash Driver} jtagspi
4895 @cindex Generic JTAG2SPI driver
4896 @cindex SPI
4897 @cindex jtagspi
4898 @cindex bscan_spi
4899 Several FPGAs and CPLDs can retrieve their configuration (bitstream) from a
4900 SPI flash connected to them. To access this flash from the host, the device
4901 is first programmed with a special proxy bitstream that
4902 exposes the SPI flash on the device's JTAG interface. The flash can then be
4903 accessed through JTAG.
4904
4905 Since signaling between JTAG and SPI is compatible, all that is required for
4906 a proxy bitstream is to connect TDI-MOSI, TDO-MISO, TCK-CLK and activate
4907 the flash chip select when the JTAG state machine is in SHIFT-DR. Such
4908 a bitstream for several Xilinx FPGAs can be found in
4909 @file{contrib/loaders/flash/fpga/xilinx_bscan_spi.py}. It requires
4910 @uref{https://github.com/m-labs/migen, migen} and a Xilinx toolchain to build.
4911
4912 This flash bank driver requires a target on a JTAG tap and will access that
4913 tap directly. Since no support from the target is needed, the target can be a
4914 "testee" dummy. Since the target does not expose the flash memory
4915 mapping, target commands that would otherwise be expected to access the flash
4916 will not work. These include all @command{*_image} and
4917 @command{$target_name m*} commands as well as @command{program}. Equivalent
4918 functionality is available through the @command{flash write_bank},
4919 @command{flash read_bank}, and @command{flash verify_bank} commands.
4920
4921 @itemize
4922 @item @var{ir} ... is loaded into the JTAG IR to map the flash as the JTAG DR.
4923 For the bitstreams generated from @file{xilinx_bscan_spi.py} this is the
4924 @var{USER1} instruction.
4925 @end itemize
4926
4927 @example
4928 target create $_TARGETNAME testee -chain-position $_CHIPNAME.fpga
4929 set _XILINX_USER1 0x02
4930 flash bank $_FLASHNAME spi 0x0 0 0 0 \
4931 $_TARGETNAME $_XILINX_USER1
4932 @end example
4933 @end deffn
4934
4935 @deffn {Flash Driver} xcf
4936 @cindex Xilinx Platform flash driver
4937 @cindex xcf
4938 Xilinx FPGAs can be configured from specialized flash ICs named Platform Flash.
4939 It is (almost) regular NOR flash with erase sectors, program pages, etc. The
4940 only difference is special registers controlling its FPGA specific behavior.
4941 They must be properly configured for successful FPGA loading using
4942 additional @var{xcf} driver command:
4943
4944 @deffn Command {xcf ccb} <bank_id>
4945 command accepts additional parameters:
4946 @itemize
4947 @item @var{external|internal} ... selects clock source.
4948 @item @var{serial|parallel} ... selects serial or parallel data bus mode.
4949 @item @var{slave|master} ... selects slave of master mode for flash device.
4950 @item @var{40|20} ... selects clock frequency in MHz for internal clock
4951 in master mode.
4952 @end itemize
4953 @example
4954 xcf ccb 0 external parallel slave 40
4955 @end example
4956 All of them must be specified even if clock frequency is pointless
4957 in slave mode. If only bank id specified than command prints current
4958 CCB register value. Note: there is no need to write this register
4959 every time you erase/program data sectors because it stores in
4960 dedicated sector.
4961 @end deffn
4962
4963 @deffn Command {xcf configure} <bank_id>
4964 Initiates FPGA loading procedure. Useful if your board has no "configure"
4965 button.
4966 @example
4967 xcf configure 0
4968 @end example
4969 @end deffn
4970
4971 Additional driver notes:
4972 @itemize
4973 @item Only single revision supported.
4974 @item Driver automatically detects need of bit reverse, but
4975 only "bin" (raw binary, do not confuse it with "bit") and "mcs"
4976 (Intel hex) file types supported.
4977 @item For additional info check xapp972.pdf and ug380.pdf.
4978 @end itemize
4979 @end deffn
4980
4981 @deffn {Flash Driver} lpcspifi
4982 @cindex NXP SPI Flash Interface
4983 @cindex SPIFI
4984 @cindex lpcspifi
4985 NXP's LPC43xx and LPC18xx families include a proprietary SPI
4986 Flash Interface (SPIFI) peripheral that can drive and provide
4987 memory mapped access to external SPI flash devices.
4988
4989 The lpcspifi driver initializes this interface and provides
4990 program and erase functionality for these serial flash devices.
4991 Use of this driver @b{requires} a working area of at least 1kB
4992 to be configured on the target device; more than this will
4993 significantly reduce flash programming times.
4994
4995 The setup command only requires the @var{base} parameter. All
4996 other parameters are ignored, and the flash size and layout
4997 are configured by the driver.
4998
4999 @example
5000 flash bank $_FLASHNAME lpcspifi 0x14000000 0 0 0 $_TARGETNAME
5001 @end example
5002
5003 @end deffn
5004
5005 @deffn {Flash Driver} stmsmi
5006 @cindex STMicroelectronics Serial Memory Interface
5007 @cindex SMI
5008 @cindex stmsmi
5009 Some devices form STMicroelectronics (e.g. STR75x MCU family,
5010 SPEAr MPU family) include a proprietary
5011 ``Serial Memory Interface'' (SMI) controller able to drive external
5012 SPI flash devices.
5013 Depending on specific device and board configuration, up to 4 external
5014 flash devices can be connected.
5015
5016 SMI makes the flash content directly accessible in the CPU address
5017 space; each external device is mapped in a memory bank.
5018 CPU can directly read data, execute code and boot from SMI banks.
5019 Normal OpenOCD commands like @command{mdw} can be used to display
5020 the flash content.
5021
5022 The setup command only requires the @var{base} parameter in order
5023 to identify the memory bank.
5024 All other parameters are ignored. Additional information, like
5025 flash size, are detected automatically.
5026
5027 @example
5028 flash bank $_FLASHNAME stmsmi 0xf8000000 0 0 0 $_TARGETNAME
5029 @end example
5030
5031 @end deffn
5032
5033 @deffn {Flash Driver} mrvlqspi
5034 This driver supports QSPI flash controller of Marvell's Wireless
5035 Microcontroller platform.
5036
5037 The flash size is autodetected based on the table of known JEDEC IDs
5038 hardcoded in the OpenOCD sources.
5039
5040 @example
5041 flash bank $_FLASHNAME mrvlqspi 0x0 0 0 0 $_TARGETNAME 0x46010000
5042 @end example
5043
5044 @end deffn
5045
5046 @deffn {Flash Driver} ath79
5047 @cindex Atheros ath79 SPI driver
5048 @cindex ath79
5049 Members of ATH79 SoC family from Atheros include a SPI interface with 3
5050 chip selects.
5051 On reset a SPI flash connected to the first chip select (CS0) is made
5052 directly read-accessible in the CPU address space (up to 16MBytes)
5053 and is usually used to store the bootloader and operating system.
5054 Normal OpenOCD commands like @command{mdw} can be used to display
5055 the flash content while it is in memory-mapped mode (only the first
5056 4MBytes are accessible without additional configuration on reset).
5057
5058 The setup command only requires the @var{base} parameter in order
5059 to identify the memory bank. The actual value for the base address
5060 is not otherwise used by the driver. However the mapping is passed
5061 to gdb. Thus for the memory mapped flash (chipselect CS0) the base
5062 address should be the actual memory mapped base address. For unmapped
5063 chipselects (CS1 and CS2) care should be taken to use a base address
5064 that does not overlap with real memory regions.
5065 Additional information, like flash size, are detected automatically.
5066 An optional additional parameter sets the chipselect for the bank,
5067 with the