ARM-USB-OCD, LPC-P2129, unreliable operation? [FIXED]

Development Boards MicroMod
1

Hi,

My hardware is:

Olimex ARM-USB-OCD JTAG interface.

Olimex LPC-P2129 (powered by 9v output of ARM-USB-OCD).

My software is:

OpenOCD r204 on Gentoo Linux, 2.6.17-gentoo-r7 running on AMD Sempron processor. I have libftdi 0.7 installed. I built openocd on this machine using

bootstrap
configure --enable-ft2232-libftdi
make
sudo make install

My config file is:

#daemon configuration
telnet_port 4444
gdb_port 3333

#interface
interface ft2232
ft2232_layout olimex-jtag
ft2232_vid_pid 0x15BA 0x0003
jtag_speed 40
#use combined on interfaces or targets that can't set TRST/SRST separately
reset_config trst_and_srst srst_pulls_trst

#jtag scan chain
jtag_device 4 0x1 0xf 0xe

daemon_startup reset
target arm7tdmi little run_and_halt 0 arm7tdmi-s_r4
run_and_halt_time 0 500

working_area 0 0x40003000 0x1000 nobackup

#flash configuration
flash bank lpc2000 0x0 0x40000 0 0 0 lpc2000_v1 calc_checksum

Problem:

If I unplug the ARM-USB-OCD from the USB interface and replug it, it works - I get:

$ openocd
Info:    openocd.c:93 main(): Open On-Chip Debugger (2007-09-05 09:00 CEST)
Warning: arm7_9_common.c:734 arm7_9_assert_reset(): srst resets test logic, too
Info:    server.c:67 add_connection(): accepted 'telnet' connection from 0
Info:    server.c:360 server_loop(): dropped 'telnet' connection

I can telnet to 4444 and execute the poll command, getting the expected results, so all is well.

Now if I execute the shutdown command to exit openocd and then re-run openocd it fails:

$ openocd
Info:    openocd.c:93 main(): Open On-Chip Debugger (2007-09-05 09:00 CEST)
Error:   jtag.c:1253 jtag_examine_chain(): JTAG communication failure, check connection, JTAG interface, target power etc.
Error:   jtag.c:1440 jtag_init(): trying to validate configured JTAG chain anyway...
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1346 jtag_validate_chain(): Error validating JTAG scan chain, IR mismatch, scan returned 0x3f
Error:   jtag.c:1448 jtag_init(): Could not validate JTAG chain, exit

At this point pressing the reset button (or power cycling) the P2129 doesn’t fix it - only unplugging and replugging the ARM-USB-OCD.

Note it doesn’t always fail first time, but always within a couple of runs.

So I am assuming the FT2232 chip or the JTAG state machine is in not in the expected state. Now I think the USB comms to the FT2232 is OK because the layout->blink() command that is executed as part of the jtag_initialise() call does make the LED blink, even when jtag_examine_chain() goes on to fail.

Any ideas about how to debug this (I’m happy to spend time in GDB, but I don’t know much about JTAG itself or the FTDI chip behaviour).

Thanks in advance for any help you can offer,

Robin Iddon

2

I resolved this by switching to using the latest version of the binary FTDI library as described by:

[clicky

Basically it would seem that libftdi is not reliable driver for the hardware for some reason.

I tried upgrading to 0.9 (which is marked unstable on Gentoo) and it was no better or worse.

Anyway, much as I dislike using proprietary binaries, in this case I will use it and move on :slight_smile:

Thanks,

Robin](http://openhardware.net/Embedded_ARM/OpenOCD_JTAG/)