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TM4C123FE6PM: Arm-based microcontrollers forum

Yamei Xiao
Prodigy 10 points
Part Number: TM4C123FE6PM
Other Parts Discussed in Thread: UNIFLASH

I have some TM4C123FE6PMI failed in use. With the failed boards, I was unable to re-flash the microcontroller.

        Here are the things I tried.

  • I was able to unlock the microcontroller using LM Flash Programmer
  • I was unable to read the memory of the microcontroller using uniflash

         When I tried to connect to target with XDS200, I got the messages below.

 -----[Print the reset-command software log-file]-----------------------------

 

This utility has selected a 560/2xx-class product.

This utility will load the program 'xds2xxu.out'.

The library build date was 'Sep 20 2022'.

The library build time was '17:17:24'.

The library package version is '9.9.0.00040'.

The library component version is '35.35.0.0'.

The controller does not use a programmable FPGA.

The controller has a version number of '13' (0x0000000d).

The controller has an insertion length of '0' (0x00000000).

This utility will attempt to reset the controller.

This utility has successfully reset the controller.

 

-----[Print the reset-command hardware log-file]-----------------------------

 

This emulator does not create a reset log-file.

 

-----[An error has occurred and this utility has aborted]--------------------

 

This error is generated by TI's USCIF driver or utilities.

 

The value is '-233' (0xffffff17).

The title is 'SC_ERR_PATH_BROKEN'.

 

The explanation is:

The JTAG IR and DR scan-paths cannot circulate bits, they may be broken.

An attempt to scan the JTAG scan-path has failed.

The target's JTAG scan-path appears to be broken

with a stuck-at-ones or stuck-at-zero fault.

 

[End]                    

 

            I checked 1 through 7 listed in your Application Report SPMA075, page 27.

            https://www.ti.com/lit/pdf/spma075

           

            1 through 6 were fine. 3.3V and 1.2V were there. 16MHz crystal on my PCB was not oscillating.

            I'm trying to understand if it’s possible to make the microcontroller work again.

  • 0
    TI__Guru*** 135355 points

    Hello Yamei,

    Can you walk through how you unlocked the microcontroller with LM Flash programmer? Did you connect the ICDI interface of a TM4C LaunchPad/Dev Kit to the failed board?

    Usually for custom boards using probes like XDS200, the unlock process needs to be done via UniFlash Command Line.

    Best Regards,

    Ralph Jacobi

  • 0 in reply to Ralph Jacobi
    Prodigy 10 points

    Yeah, I was using a TM4C Launch Pad to unlock the microcontroller. Powered up the board, while holding down the rest button on Launch Pad. Exactly as described in section 5.3.1.

  • 0 in reply to Yamei Xiao
    TI__Guru*** 135355 points

    Hello Yamei,

    Did you have the RESET button of the LaunchPad connected to the /RESET pin of your TM4C123FE6PMI? The instructions regarding holding down reset refers to the /RESET pin of the microcontroller you are trying to unlock.

    The GUI is not able to detect if you are properly executing that step, so if the /RESET pin of the TM4C123FE6PMI was not held down properly, it would falsely remark the unlock was successful.

    Best Regards,

    Ralph Jacobi

  • 0 in reply to Ralph Jacobi
    Prodigy 10 points

    Good to know. I had a jumper that connected the /RESET header on LaunchPad to the /RESET pin on my microcontroller. 

  • 0 in reply to Yamei Xiao
    TI__Guru*** 135355 points

    Hello Yamei,

    Alright, just wanted to be certain that the unlock process was done properly. Generally that should be enough to recover the device and restore JTAG even if bad code was loaded or the code hit a fault that locked out JTAG...

    Can you probe the TDO signal and see if it's toggling at a constant rate?

    You said the board is failed in use, so my understanding is then is that you have an existing validated design that failed in the field and you are trying to either debug or recover the board?

    If so, do you have the ability to do an ABA swap so we can find out if the issue is isolated to the TM4C micro specifically?

    Best Regards,

    Ralph Jacobi

  • 0 in reply to Ralph Jacobi
    Prodigy 10 points

    TDO was not toggling at all. 

    I was trying to debug. If I replace the microcontroller, it would work. 

  • 0 in reply to Yamei Xiao
    TI__Guru*** 135355 points

    Hello Yamei,

    I would suggest testing the microcontroller pins to see if there is any evidence of a possible short then. If the unlock process is succeeding but the MCU can't be programmed, I would expect some sort of damage has occurred whether it was ESD or an overvoltage/current. The unlock process results in Flash being completely cleared and registers being reset so nothing should prevent JTAG access at that point. 

    You may also want to see if the device is sinking more current on a failed board versus a functional board.

    Best Regards,

    Ralph Jacobi