# Strange error when connecting JTAG

My setup:

Common) CPU: at91sam7x512, JTAG: olimex-arm-usb-tiny-h, proprietary single-CPY board
1) Windows 7, OpenOCD 0.0.4 <- works 2) Ubuntu 13.04, OpenOCD 0.7.0 <- strange error

There are some config files written in past times and the windows version works. Now I am trying to make things work under linux.

The manufacturer's page doesn't seem to have a ready config file, although they have instructions for building OpenOCD.

I built it with ft2232 support. OpenOCD seems to locate the JTAG, but not the device:

sw3@pc90313-sw3:~/ocd_conf$openocd -f ocdconfig.cfg Open On-Chip Debugger 0.7.0 (2013-08-16-13:27) Licensed under GNU GPL v2 For bug reports, read http://openocd.sourceforge.net/doc/doxygen/bugs.html Info : only one transport option; autoselect 'jtag' adapter speed: 20 kHz srst_only srst_pulls_trst srst_gates_jtag srst_open_drain connect_deassert_srst Info : device: 6 "2232H" Info : deviceID: 364511274 Info : SerialNumber: OLWKRKY?A Info : Description: Olimex OpenOCD JTAG ARM-USB-TINY-H A Info : max TCK change to: 30000 kHz Info : clock speed 20 kHz fError: couldn't read enough bytes from FT2232 device (70 < 81) Error: couldn't read from FT2232 Error: Trying to use configured scan chain anyway... Warn : Bypassing JTAG setup events due to errors Info : Embedded ICE version 1 Info : sam7x512.cpu: hardware has 2 breakpoint/watchpoint units  Here is my config file: sw3@pc90313-sw3:~/ocd_conf$ cat ocdconfig.cfg
source [find interface/olimex-arm-usb-tiny-h.cfg]

source [find target/at91sam7x512.cfg]


This error Error: couldn't read enough bytes from FT2232 device (70 < 81) seems to be the give-away. Other people in Googleland have experienced similar problems, but with (0 < 81) in which case it is clear that communication is not working at all. In my case, the number oscillates at 69-79-71.

Ideas?

The FT2232H uses High Speed USB, and the error translates into "problem in USB communication". Id recommend trying another USB cable first - but this seems not to be a problem here, as it works in other configurations.

You should use the newer ftdi driver in OpenOCD 0.7.0:

source [find interface/ftdi/olimex-arm-usb-tiny-h.cfg]


You can ignore the warning, the interface was tested to be OK, but after the 0.7.0 release.

Updating the OpenOCD windows binaries might be a good idea, too - the 0.4.0 release is getting rusty.

• I ... am not sire if this worked. There are no errors with the new interface. Is openocd supposed to run as a deamon so that I can connect to it from e.g. gdb, or is it supposed to enter interactive mode and expect commands? – Vorac Aug 19 '13 at 12:39
• Deamon mode: Use telnet localhost 4444` in another console. You might also want to RTFM. – Turbo J Aug 19 '13 at 12:47
• OK, thanks. TFM is 150 pages ... I'm going through it, but am not understanding everything at the first run. – Vorac Aug 19 '13 at 12:51
• Thanks, changing the interface eliminated the error. I was suspecting my libftd2xx.so and looping in circles until your answer. l – Vorac Aug 19 '13 at 13:29