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Thread: Teensy 4 - Debug pins

  1. #1

    Teensy 4 - Debug pins

    Hi Guys,

    Is there anyway of connecting JTAG or similar to the Teensy 4?



  2. #2
    Junior Member
    Join Date
    Mar 2019

    Cool Debugging

    Quote Originally Posted by AndyCap View Post
    Hi Guys,
    Is there anyway of connecting JTAG or similar to the Teensy 4?
    I asked this in thread "Debugger Depression" - and got no answer to it yet.
    So I guess, there are no JTAG Pins.
    Otherwise we would have received an answer

    If this is true, i would be a sad thing, for projects on a board with so much RAM are often quite complex and Debugging would be very useful.

    I also asked for it some time before Teensy 4.0 was released - Paul could still have added it, if he had found it important.
    But he did not change Teensy 3.6's firmware as well for easier Debugging.

    All in all it seems to me, he is not really interested in this feature.

    I would love that you proof me wrong here

  3. #3
    Hi Martin,

    Thanks for the info, seems a bit weird as the 3.6 had the debug pins.

    I cannot see anything on the 4 pinout though, I was just hoping I was wrong!.


  4. #4
    Wishlist for future (to support the view of MartinZ that debugging would be valuable)
    I believe that enabling debugger pins and on-chip ethernet support would improve the applicability of Teensy in automation and robotics. Teensy has much what is needed in these applications, like good form factor and design, lot of power, it can be plugged into an application-specific board, can be used in commercial products, etc. Just these two things have kept us putting STM32F429, etc, directly on IO boards, instead of using Teensy as ready processor module and saving a truckload of development and testing work:

    Debugger support and enabled on-chip Ethernet.

    On-chip Ethernet: Ethernet is de facto cabling in many automation systems. I use LWIP without FreeRTOS, etc on STM32F429, and it works fine (works from both STM32duino and True Studio). So I assume it could be made work also as well in Teensy. It would be a better solution than using Wiz chip. No need to fit RS45 on Teensy, maybe not even PHY chip. I imagine Teensy to be plugged into a bigger board, which contains application-specific IO and could contain RJ45/PHY as well. So Ethernet should be part of pin stips at edges of Teensy board.

    Debugger: Enabling hardware debugger is like insurance. Hopefully not really needed, but if needed worth a lot. I would be hesitant to start a serious professional development project without a debugger, risk reduction having working debugger is reason enough for selecting extra cost and less optimal hardware. Small JTAG Cortex-M Debug connector could be directly on Teensy board.

    Background: software, automation, and measurement robotics development in private corporations.

    Just related hackaday links.

    This is about 3.6 debug pins. To my knowledge, it is still a reality that Kinetix chip needs to be removed from Teensy to use a debugger. I read that this would not be needed if boot loader would be modified.

    If the debugging pins were truly available, I believe that following gdb debug could work for TeensyDuino development with Arduino IDE. I used it on STM32 chips, it is a little cumbersome but works fine.
    Last edited by pekkalehtikoski; 08-16-2019 at 08:57 PM.

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