JTAG progress on Linkstation Mini

pabr · **Joined:** Sun Jun 21, 2009 11:39 am **Posts:** 13

Here is my understanding of JTAG on the Linkstation Mini:

- CN7 is a 1mm-pitch 1x10 connector with the same pin numbering as CN3 here: http://buffalo.nas-central.org/wiki/Install_a_JTAG_Port

- Bridge TMS to JT_TMS_CPU and JT_TMS_CORE at C227 and C228 (top side, near the CPU). I have no idea why these pads are labelled as "C"s.

- Bridge JT_TDO to TDO at the two vias under C25 (near CN7). Do it on the bottom side.

OpenOCD says

Code:

Info : JTAG tap: feroceon.cpu tap/device found: 0x25182357 (mfg: 0x1ab, part: 0x5182, ver: 0x2)

The halt command causes the board to freeze (serial console is unresponsive and software-controlled leds stop blinking) but OpenOCD does not consider the CPU halted. I read that halting is unreliable on other linkstations too. Any ideas ?

pabr · **Joined:** Sun Jun 21, 2009 11:39 am **Posts:** 13

Hmm, maybe I got the tap IDs wrong.

If I bridge only C227, OpenOCD sees part 0x7926, and I can reliably halt the CPU and probe the flash:

Code:

Open On-Chip Debugger
> reset
JTAG tap: feroceon.cpu tap/device found: 0x07926041 (mfg: 0x020, part: 0x7926, ver: 0x0)
JTAG Tap/device matched
> halt
target state: halted
target halted in ARM state due to debug-request, current mode: Supervisor
cpsr: 0x800000d3 pc: 0x00f3aac0
MMU: disabled, D-Cache: disabled, I-Cache: enabled
> flash probe 0
Flash Manufacturer/Device: 0x00bf 0x00d6
flash 'cfi' found at 0xfffc0000
> dump_image currentcontents.bin 0xfffc0000 0x40000
dumped 262144 byte in 156.199112s

If I bridge both C227 and C228, or C228 only, OpenOCD sees only part 0x5182.

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JTAG progress on Linkstation Mini

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