BBB: Do I gain anything by adding the JTAG header and using a JTAG debug pod?

BBB: Do I gain anything by adding the JTAG header and using a JTAG debug pod?

I’m wondering the same thing…

More generally when to JTAG vs. utilizing all of the other tools out there for debugging Linux (e.g. GDB server).

We recently tried to bring up a custom board with the am5718. We were focused on booting the board in stages (e.g. first try to get the SPL to boot, then SPL to load u-boot, etc, etc). Since we were trying to tailor (and will still be engaged in this) Linux to work with our hardware, we realized that JTAG debugging would probably be useful to figure out what the processor is doing and how far the SPL gets. Then later on, once we get u-boot running and the kernel booting, we can switch over to other debug tools… JTAG may also be useful for debugging some of the other processors on the Sitara chip which don’t run Linux such as the PRU, C66 DSPs and IPU’s… but don’t yet have any experience with that…

Our initial board design (now being re-spun) with the 5718 only provided a UART for console on UART 10 (with the allowed IO sets/ pad configuration), thus we attempted to switch from UART 3 to 10, but could get nothing to come out on the console. We hooked up the blackhawk JTAG connector to the custom board (which populates JTAG), to attempt to look for “signs of life” on the processor and on the board. We were able to see that the processor wasn’t correctly responding to the JTAG tests initiated by CCS. We then connected JTAG to the BeagleBoard-X15’s JTAG and were able to run through the JTAG test procedure and view the 5728’s internal registers. We haven’t yet gotten around to loading the SPL with symbol information via CCS to the JTAG, but this might be something we try to do once the next revision of our board comes in…

Hopefully this is helpful…