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Blinkinlabs / JTAG_hat

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Use of UrJTAG #2

Open hexxor opened 10 months ago

hexxor commented 10 months ago

I wanted to know wether the JTAG HAT can be used with urJTAG and if yes, what is the configuration required? I assume it could be helpful to identify the target if not known. Like described in 3.1.3 under http://urjtag.org/book/_usage.html

The contents of the config file .jtag/rc could look like:

cable gpio tck=10 tms=9 tdi=11 tdo=25 detect discover

Any pointers or experience?

cibomahto commented 10 months ago

I haven't tried it!

The only issue that I see is that because the signal pins are buffered, if you want to switch the direction of the TMS pin, you need to pull a separate pin (GPIO 16) high or low (see the schematic)

We added support for this in OpenOCD, but I don't see it in the urJTAG gpio cable driver.

I think this is only an issue with SWD targets, though.