[ABANDONED] iMX537: Unpredictable connection/reset/halt behavior

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  • [ABANDONED] iMX537: Unpredictable connection/reset/halt behavior

    We are experiencing unpredictable behavior when using J-Link Commander to control an iMX537. In particular, it doesn't always connect. And, we can't always halt the processor.

    We are running with a Freescale iMX537 on a custom board using a J-Link Plus with updated firmware. I have verified that all of the JTAG signals are making it to the board correctly using the commands 0, 1, t0, t1, trst0, trst1, tck0, tck1, r0, r1. I also verified the RESET line coming from the JTAG connector and that J-Link can reset the processor causing code to execute. Voltages look good.

    When we first connect, we see a bunch of "WARNING: At least one of the connected devices is not JTAG compliant" messages. When I exit out and quickly re-run J-Link Commander, it seems to connect up to the iMX53. If I do halt/go commands (see below), eventually it displays "WARNING: CPU could not be halted".
    Any clues about what might cause this type of behavior? Is there a special iMX537 reset sequence or configuration required? (note that I tried using the supplied iMX23 JLinkScript and this did not improve things).

    See the attached log and session output from J-Link Commander below.
    Thanks
    Files
    • jlink.txt

      (60.57 kB, downloaded 211 times, last: )
    • session.txt

      (5.64 kB, downloaded 220 times, last: )
  • Hello,

    Thank you for your inquiry.

    When we first connect, we see a bunch of "WARNING: At least one of the connected devices is not JTAG compliant" messages.


    For the IMX devices this is expected behaviour and is not problematic for J-Link.

    If I do halt/go commands (see below), eventually it displays "WARNING: CPU could not be halted".


    I tried to reproduce this with a IMX535 board we have at hand and could not reproduce this issue. I could halt and run and halt again without any issues.
    Is it possible that you are booting some kind of OS (e.g. Linux) on this chip while debugging? In that case it is possible that the booting OS is reinitializing all
    GPIO function pins and thus the JTAG connection gets interrupted.
    Make sure that the programs you are loading on your device do not reset the JTAG pin configuration.

    Best regards,
    Nino
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