From: Antonio Borneo Date: Mon, 24 Sep 2018 13:26:40 +0000 (+0200) Subject: stlink: remove reset pulse when entering in JTAG X-Git-Tag: v0.11.0-rc1~927 X-Git-Url: https://review.openocd.org/gitweb?p=openocd.git;a=commitdiff_plain;h=717d3af0879633a5c2d2a711db126cf0091e5930 stlink: remove reset pulse when entering in JTAG Until version J14 the behaviour of ST-Link was to send a reset pulse to the target when the debug connection is started in JTAG mode. No reset pulse is sent, instead, in SWD mode. Version J15 introduces a new parameter to avoid the reset pulse in JTAG mode, aligning the behaviour with SWD. This reset from the ST-Link, if propagated to the target, prevents attaching a running target. Actually this reset pulse is very short (few microsecond) and can be easily filtered out by an on-board capacitor, usually present on the reset wire (mainly to filter the bounces of the reset button). Moreover, most of the use cases for ST-Link are with SWD (not with JTAG) and this has probably further masked this JTAG specific behaviour. OpenOCD can tolerate it but requires the flag "connect_assert_srst" to the command "reset_config", but the flag is not present in any configurations in folder tcl. This enforces the guess it was not noticed due to on-board capacitors or missing connection of reset pin or ST-Link only used in SWD; so it's safe applying this patch. Change the default behaviour to avoid reset in JTAG at connection. There is no need to manage the ST-Link version here, since every parameter that is not recognized by older ST-Link is treated as "connect in JTAG with reset pulse", keeping backward compatibility. Change-Id: Idc97a1457279e3970fd0839cadbff22d9b0302d4 Signed-off-by: Antonio Borneo Reviewed-on: http://openocd.zylin.com/4713 Tested-by: jenkins Reviewed-by: Spencer Oliver --- diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c index 5c5fde9521..f05ffadf9e 100644 --- a/src/jtag/drivers/stlink_usb.c +++ b/src/jtag/drivers/stlink_usb.c @@ -205,7 +205,6 @@ struct stlink_usb_handle_s { #define STLINK_SWIM_READMEM 0x0b #define STLINK_SWIM_READBUF 0x0c -#define STLINK_DEBUG_ENTER_JTAG 0x00 #define STLINK_DEBUG_GETSTATUS 0x01 #define STLINK_DEBUG_FORCEDEBUG 0x02 #define STLINK_DEBUG_APIV1_RESETSYS 0x03 @@ -223,8 +222,9 @@ struct stlink_usb_handle_s { #define STLINK_DEBUG_APIV1_WRITEDEBUGREG 0x0f #define STLINK_DEBUG_APIV1_SETWATCHPOINT 0x10 -#define STLINK_DEBUG_ENTER_JTAG 0x00 -#define STLINK_DEBUG_ENTER_SWD 0xa3 +#define STLINK_DEBUG_ENTER_JTAG_RESET 0x00 +#define STLINK_DEBUG_ENTER_SWD_NO_RESET 0xa3 +#define STLINK_DEBUG_ENTER_JTAG_NO_RESET 0xa4 #define STLINK_DEBUG_APIV1_ENTER 0x20 #define STLINK_DEBUG_EXIT 0x21 @@ -830,7 +830,7 @@ static int stlink_usb_mode_enter(void *handle, enum stlink_mode type) h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV1_ENTER; else h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_ENTER; - h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_ENTER_JTAG; + h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_ENTER_JTAG_NO_RESET; break; case STLINK_MODE_DEBUG_SWD: h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_COMMAND; @@ -838,7 +838,7 @@ static int stlink_usb_mode_enter(void *handle, enum stlink_mode type) h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV1_ENTER; else h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_APIV2_ENTER; - h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_ENTER_SWD; + h->cmdbuf[h->cmdidx++] = STLINK_DEBUG_ENTER_SWD_NO_RESET; break; case STLINK_MODE_DEBUG_SWIM: h->cmdbuf[h->cmdidx++] = STLINK_SWIM_COMMAND;