# SPDX-License-Identifier: GPL-2.0-or-later # # script for Atmel SAMD, SAMR, SAML or SAMC, a Cortex-M0 chip # # # samdXX devices only support SWD transports. # source [find target/swj-dp.tcl] if { [info exists CHIPNAME] } { set _CHIPNAME $CHIPNAME } else { set _CHIPNAME at91samd } if { [info exists ENDIAN] } { set _ENDIAN $ENDIAN } else { set _ENDIAN little } # Work-area is a space in RAM used for flash programming # By default use 2kB if { [info exists WORKAREASIZE] } { set _WORKAREASIZE $WORKAREASIZE } else { set _WORKAREASIZE 0x800 } if { [info exists CPUTAPID] } { set _CPUTAPID $CPUTAPID } else { set _CPUTAPID 0x4ba00477 } swj_newdap $_CHIPNAME cpu -irlen 4 -expected-id $_CPUTAPID dap create $_CHIPNAME.dap -chain-position $_CHIPNAME.cpu set _TARGETNAME $_CHIPNAME.cpu target create $_TARGETNAME cortex_m -endian $_ENDIAN -dap $_CHIPNAME.dap $_TARGETNAME configure -work-area-phys 0x20000000 -work-area-size $_WORKAREASIZE -work-area-backup 0 # SAMD DSU will hold the CPU in reset if TCK is low when RESET_N # deasserts (see datasheet Atmel-42181E–SAM-D21_Datasheet–02/2015, section 12.6.2) # # dsu_reset_deassert configures whether we want to run or halt out of reset, # then instruct the DSU to let us out of reset. $_TARGETNAME configure -event reset-deassert-post { at91samd dsu_reset_deassert } # SRST (wired to RESET_N) resets debug circuitry # srst_pulls_trst is not configured here to avoid an error raised in reset halt reset_config srst_gates_jtag # Do not use a reset button with other SWD adapter than Atmel's EDBG. # DSU usually locks MCU in reset state until you issue a reset command # in OpenOCD. # SAMD runs at SYSCLK = 1 MHz divided from RC oscillator after reset. # Other members of family usually use SYSCLK = 4 MHz after reset. # Datasheet does not specify SYSCLK to SWD clock ratio. # Usually used SYSCLK/6 is slow, testing shows that debugging can # work @ SYSCLK/2 but your mileage may vary. # This limit is most probably imposed by incorrectly handled SWD WAIT # on some SWD adapters. adapter speed 400 # Atmel's EDBG (on-board cmsis-dap adapter of Xplained kits) works # without problem at maximal clock speed. Atmel recommends # adapter speed less than 10 * CPU clock. # adapter speed 5000 if {![using_hla]} { # if srst is not fitted use SYSRESETREQ to # perform a soft reset cortex_m reset_config sysresetreq } set _FLASHNAME $_CHIPNAME.flash flash bank $_FLASHNAME at91samd 0x00000000 0 1 1 $_TARGETNAME