JTAG scan chain interrogation failed: all zeroes

daniel-k / rpi3-aarch64-jtag

Starting point for bare metal development and JTAG debugging on Raspberry Pi 3.

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JTAG scan chain interrogation failed: all zeroes #2

Open Makogan opened 7 years ago

Makogan commented 7 years ago

I am getting this error when trying to connect a seggers jtag device to a raspberry pi 3 board, what could be the issue?

AbdullahSarhan commented 7 years ago

Were u able to fix it?

daniel-k commented 7 years ago

I don't currently have a debugger to test again, so I'm afraid I cannot help much. But "all zeroes" sounds like there might be a cabling problem. Or the Rpi is not yet configured to answer JTAG requests.

Back in the day I used an Olimex ARM JTAG, maybe there are differences in OpenOCD ...

If you solve it I'd be eager to hear about the solution!

daniel-k commented 7 years ago

Furthermore there has been further progress on the OpenOCD side on the aarch64 support, most notably by Matthias Wählisch, but I'm not entirely sure if all his patches have already been merged upstream. Anyway you might want to try OpenOCD git-master.

henrychoi commented 6 years ago

I get the same problem if I forget to change the RPi GPIO pins to ALT functions, to enable JTAG. Please double-check that you have done this, and your TDO line is bouncing in the logic analyzer capture.