diff options
| author | Antonio Borneo <borneo.antonio@gmail.com> | 2018-09-24 15:26:40 +0200 |
|---|---|---|
| committer | Spencer Oliver <spen@spen-soft.co.uk> | 2018-12-06 13:05:44 +0000 |
| commit | 717d3af0879633a5c2d2a711db126cf0091e5930 (patch) | |
| tree | b81e5932616e8a8a13bfa78b8d7808a916772599 | |
| parent | 80ce68b42cd1851f0c77a2e0fa88bb44ec15c0b7 (diff) | |
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 <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/4713
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
| -rw-r--r-- | src/jtag/drivers/stlink_usb.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/src/jtag/drivers/stlink_usb.c b/src/jtag/drivers/stlink_usb.c index 5c5fde95..f05ffadf 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; |