A simple USB-JTAG interface implemented using LUFA library running AT90USB162 based on Open Hardware board opendous. Primary reason is to create a cheap replacement for the parallel port JTAG adapter "Wiggler" and alike.
Connecting pins to JTAG interface
PORTB is used for JTAG communications, with following pins configuration:
| Pin | Function |
| 0 | TDI |
| 1 | TMS |
| 2 | TRST |
| 3 | SRST |
| 4 | TCK |
| 5 | TDO |
Various JTAG cable pin outs are available here: http://www.jtagtest.com/pinouts/
Configuring openocd
get the rev 1454 of openocd:
svn export -r 1454 http://svn.berlios.de/svnroot/repos/openocd/trunk openocd
apply the patch from patches subdirectory:
cd openocd patch -p0 < ../opendous-jtag/patches/openocd-r1454.patch
Run the ./bootstrap script to refresh autoconf/automake rules, and then run ./configure
./bootstrap ./configure --prefix=/opt/arm --enable-opendous make make install
make sure that PATH includes /opt/arm/bin directory, run openocd:
openocd -f interface/opendous -f target/<your cpu target>
Testing speed
At the moment it is quite slow, following is a test of uploading binary on a blackfin cpu using gdbproxy:
(gdb) load u-boot Loading section .text, size 0x15d30 lma 0x3fc0000 Loading section .rodata, size 0x5ba4 lma 0x3fd5d30 Loading section .data, size 0x4100 lma 0x3fdb8d4 Loading section .u_boot_cmd, size 0x658 lma 0x3fdf9d4 Loading section .text_l1, size 0x2c lma 0x3fe002c Start address 0x3fc0000, load size 131160 Transfer rate: 2892 bits/sec, 10930 bytes/write.
Test of loading a FreeRTOS demo project on a Stellaris LM3S2965 demo kit
> openocd -f opendous.cfg -f target/lm3s6965.cfg Info : OPENDOUS JTAG Interface ready Info : JTAG tap: lm3s6965.cpu tap/device found: 0x3ba00477 (Manufacturer: 0x23b, Part: 0xba00, Version: 0x3) Info : JTAG Tap/device matched Warn : no telnet port specified, using default port 4444 Warn : no gdb port specified, using default port 3333 Warn : no tcl port specified, using default port 6666 Info : accepting 'telnet' connection from 0 target state: halted target halted due to undefined, current mode: Thread xPSR: 0x00000000 pc: 0x00000000 Info : JTAG tap: lm3s6965.cpu tap/device found: 0x3ba00477 (Manufacturer: 0x23b, Part: 0xba00, Version: 0x3) Info : JTAG Tap/device matched > halt target was in unknown state when halt was requested > flash probe 0 flash 'stellaris' found at 0x00000000 > flash erase_sector 0 0 255 erased sectors 0 through 255 on flash bank 0 in 0.811001s > flash write_image RTOSDemo.bin 0 bin Algorithm flash write 2048 words to 0x0, 18758 remaining Algorithm flash write 2048 words to 0x2000, 16710 remaining Algorithm flash write 2048 words to 0x4000, 14662 remaining Algorithm flash write 2048 words to 0x6000, 12614 remaining Algorithm flash write 2048 words to 0x8000, 10566 remaining Algorithm flash write 2048 words to 0xa000, 8518 remaining Algorithm flash write 2048 words to 0xc000, 6470 remaining Algorithm flash write 2048 words to 0xe000, 4422 remaining Algorithm flash write 2048 words to 0x10000, 2374 remaining Algorithm flash write 326 words to 0x12000, 326 remaining wrote 75032 byte from file RTOSDemo.bin in 25.443260s (2.879876 kb/s)
