Teensy 4.1 debug with JTAG (and SWD) really impossible?

[drn@nadler.com]

Professional developers rely on JTAG or SWD debuggers for work with FreeRTOS, Zephyr, and bare-metal applications (especially driver and other low-level debugging). I normally use a Segger J-Link with dozens of Cortex-M and other processors (normally SWD, but it supports JTAG as well).

I'm another one who purchased some Teensy 4.1 before I realized no SWD or JTAG connector was available or it seems possible. The standard Teensy 4.1 would be great for some of our applications but good debug support is required to do our work cost-effectively...

I searched through this forum, and I think I understand:
- SWD is not possible because of irreversible fuse settings in Teensy
- JTAG is potentially possible but power management of IMXRT1062 precludes just removing the MKL02 and tacking on a few wires
- true breakpoints are not possible due to fuse settings (??)

I think the final word is here:
- power sequence requirements and JTAG connections: https://www.pjrc.com/store/ic_mkl02_t4.html
Other folks trying very hard to find a good debug solution:
- https://forum.pjrc.com/threads/71167-4-1-latest-schematics?p=313399#post313399
- https://forum.pjrc.com/threads/66180-Teensy-4-1-Debug-Mod-Project
- https://forum.pjrc.com/threads/57365-Teensy-4-0-how-to-connect-a-jtag-debugger?highlight=segger
- https://forum.pjrc.com/threads/6137...ugger-first-Beta?p=243249&posted=1#post243249
- https://forum.pjrc.com/threads/70336-Teensy-4-1-debugging?highlight=4.1+segger

Do I understand correctly?
Has anybody found a good hardware debug solution or is this really hopeless?
Thanks in advance,
Best Regards, Dave

 

[KurtE]

I learned to live without it... But I am retired so I can take the time

It has been a while since I tried it, but there is a GDB Stub that was created to give you some debug support.
And VisualMicro has added support for this with their setup: https://www.visualmicro.com/page/Teensy-GDBDebugging.aspx

Details about this is also in the thread: https://forum.pjrc.com/threads/61373-Using-GDB-with-Teensy-without-hardware-debugger-first-Beta

 

[drn@nadler.com]

Thanks KurtE, but those solutions are specific to Arduino and limited.
GDB stub can be used with other environments as well, but provides significantly less capability than a real hardware debugger...