Talk:Software SSH Shell Activation

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Revision as of 12:55, 28 September 2007 by Philipp (talk | contribs)
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I've just received a JTAG cable, and intend to use a variation on the procedure described here to attempt ressurect my bricked IR100. As this will be my first experience with JTAG, I have a few questions. My cable does not have an nTRST, should I leave that connection on the board floating, or tie it to GND or VCC? And am I correct in assuming that GND is the circles with dots in them in Barracuda-board-outline.jpg, and that VCC can be connected to the VSS2 that is just outside the circle with the JTAG connection points? Also does anyone have any recommendations for Linux based software for using my wiggler compatible JTAG cable. I'm currently considering OpenOCD or the Openwince JTAG tools, but are there better options, or is there are reason to choose one over the other? And finally, when programming via JTAG, do I need to have the Barracuda board plugged into the radio and powered up, or is power supplied through the parallel port so I can work on just the board on my bench?

--Jpr 12:38, 27 September 2007 (CEST)

OK, I'm starting to understand this myself from reading various webpages about connecting JTAG cables to various other hardware. VCC needs to be connected to +3.3V line and provides power to the buffer chip on the JTAG adapter, not the other way around. I see that although there are six wires coming out of the JTAG adapter, there are only 5 connected to the DB25 socket, and VCC is the one that is missing. VSS is GND, not VCC, and the circles with dots seem to be connecting the layers of the board, and could be anything. Finally it seems I need to tie nTRST high (if it is not already tied through a resistor on the board, I'll check first, as I want to minimise the risk of heat damage and shorts as I solder onto those tiny pads).

--Jpr 14:54, 27 September 2007 (CEST)

I've now started documenting my progress on Unbricking. The basic JTAG connection seems to be working, I can halt the processor, single step, and list the registers with OpenOCD, and openwince-jtag also seems to talk OK, though it doesn't recognize the processor OOTB so you cant do much. Some patches seem to be required to get OpenOCD to read/write NAND flash, and this seems to be the most promising route so far.