Teensy 4.1 and Raspberry Pi Debugger

[wearyhacker]

Raspberry Pi have just a launched a debug probe based on their Raspberry Pi PICO board. See announcement here and documentation here.

I have one and it is a nice little piece of kit. I am planning to attempt using it with Teensy 4.1 modded for JTAG.

1. Has anyone already tried this?
2. Does anyone have any suggestions?
3. Is it actually possible?

It would be nice to able to get CMSIS-DAP working with a Teensy.

Thanks,

Roger

 

[PaulStoffregen]

It absolutely will not work. Raspberry Pi Pico uses SWD protocol. Teensy 4.1 uses JTAG protocol. That hardware isn't capable of JTAG. Even if different firmware were written, it simply doesn't have enough pins for JTAG.

See this thread for details and some tips that will (probably) help if you decide to try with a JTAG-capable probe (eg, Segger J-Link).

https://forum.pjrc.com/threads/71167-4-1-latest-schematics?p=313400&viewfull=1#post313400

 

[wearyhacker]

Thanks Paul,

I had not looked much further than the fact that it supported CMSIS-DAP on the USB side, and that on the target side CMSIS-DAP is supposed either JTAG or SWD. It looks like it would require a firmware change and probably also a hardware mod in the probe to support JTAG.

Roger

 

[wearyhacker]

Just a little bit more info.

The DEBUG port on the target side of the probe is actually a cJTAG port. This is 2-wire bus one wire is clock the other is bidirectional data. I wonder if the MIMXRT1062DVJ6B supports that? With a quick search I could not find any reference other than full JTAG.

 

[PaulStoffregen]

I wonder if the MIMXRT1062DVJ6B supports that?

Pretty sure it does not support cJTAG.