Hi,
I have a box that I’m trying to hack. It’s missing trst and srst pins on board, so I basically followed
Amontec JTAGkey or Amontec JTAG-Tiny allow the TRST_N and SRST_N signals to be tristated (drive ‘0’, drive ‘1’, open-drain).
When open-drain, the ‘1’ MUST be fixed by an external pull-up (pull-up on your target board), and the ‘0’ will be drive by the JTAGkey buffer.
For OpenOCD you have to use in the configuration file:
reset config [combination] [trst-type] [srst-type]
is one of none, trst_only, srst_only or trst_and_srst.
[combination] is one of srst_pulls_trst, trst_pulls_srst, combined, separate.
[trst-type] is one of trst_open_drain, trst_push_pull.
[srst-type] is one of srst_push_pull, srst_open_drain.
Laurent
Also I cheated and took the configuration from one of the posting here.
It looks like
telnet_port 4444
gdb_port 8888
interface ft2232
ft2232_device_desc “Amontec JTAGkey A”
ft2232_layout jtagkey
ft2232_vid_pid 0x0403 0xcff8
jtag_speed 0
jtag_device 5 0x1 0x1f 0x1e
jtag_nsrst_delay 200
jtag_ntrst_delay 200
daemon_startup reset
target xscale little run_and_halt 0 pxa255
reset_config none combined trst_open_drain srst_open_drain
run_and_halt_time 0 30
Then I tried openocd, and the output from open ocd show below
Info: openocd.c:86 main(): Open On-Chip Debugger (2007-04-11 16:20 CEST)
Debug: jtag.c:1335 jtag_init(): -
Debug: ft2232.c:1268 ft2232_init(): ‘ft2232’ interface using FTD2XX with ‘jtagkey’ layout
Debug: ft2232.c:1354 ft2232_init(): current latency timer: 2
Debug: ft2232.c:1528 jtagkey_init(): 80 08 1b
Debug: ft2232.c:1586 jtagkey_init(): 82 0c 0f
Debug: ft2232.c:246 ft2232_speed(): 86 00 00
Debug: jtag.c:278 jtag_call_event_callbacks(): jtag event: TRST asserted
Debug: jtag.c:1126 jtag_reset_callback(): -
Debug: jtag.c:278 jtag_call_event_callbacks(): jtag event: TRST asserted
Debug: jtag.c:1126 jtag_reset_callback(): -
Error: jtag.c:1230 jtag_examine_chain(): number of discovered devices in JTAG chain (0) doesn’t match configuration (1)
Can anyone help me out?