Unable to connect to an i.mx27 litekit

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  • Unable to connect to an i.mx27 litekit

    Hello,
    last week I was working on the i.mx27 litekit with J-Link, everything worked well, but now (I'm not sure when it has begun) J-Link refuses to connect the board with following message.

    Source Code

    1. SEGGER J-Link Commander V4.30 ('?' for help)SEGGER J-Link Commander V4.30 ('?' for help)
    2. Compiled Jun 30 2011 15:53:19
    3. DLL version V4.30, compiled Jun 30 2011 15:53:15
    4. Firmware: J-Link ARM V8 compiled Jul 5 2011 20:48:23
    5. Hardware: V8.00
    6. S/N: 58004787
    7. VTarget = 1.785V
    8. Info: Could not measure total IR len. TDO is constant high.
    10. WARNING: CPU core not found.
    11. No devices found on JTAG chain. Trying to find device on SWD.
    13. WARNING: CPU core not found.
    14. No device found on SWD.
    15. Did not find any core.
    16. Info: Could not measure total IR len. TDO is constant high.
    18. WARNING: CPU core not found.
    19. No devices found on JTAG chain. Trying to find device on SWD.
    21. WARNING: CPU core not found.
    22. No device found on SWD.
    23. Did not find any core.Did not find any core.
    Display All

    Also, the board resets after running JLink commander.

    I'm afraid I could break the JTAG pins with statics, but I discovered that when I hold the reset button, j-link connects

    Source Code

    1. SEGGER J-Link Commander V4.30 ('?' for help)SEGGER J-Link Commander V4.30 ('?' for help)
    2. Compiled Jun 30 2011 15:53:19
    3. DLL version V4.30, compiled Jun 30 2011 15:53:15
    4. Firmware: J-Link ARM V8 compiled Jul 5 2011 20:48:23
    5. Hardware: V8.00
    6. S/N: 58004787
    7. VTarget = 1.785V
    8. Info: TotalIRLen = 8, IRPrint = 0x0011
    9. Found 2 JTAG devices, Total IRLen = 8:
    10. #0 Id: 0x1B900F0F, IRLen: 04, IRPrint: 0x0, ARM ETB
    11. #1 Id: 0x07926121, IRLen: 04, IRPrint: 0x1, ARM926EJ-S Core
    12. Found ARM with core Id 0x07926121 (ARM9)
    13. ETM V1.3: 4 pairs addr.comp, 2 data comp, 8 MM decs, 2 counters, sequencer
    14. JTAG speed: 100 kHzJTAG speed: 100 kHz
    Display All
    Do you please have any suggestion to this problem?
    regards
    Jan

  • Hi Jan,

    is it possible that something has been programmed into the flash which prevents J-Link from connecting to the board?
    For example: JTAG pins are remapped by the target application, CPU clock is cut off, debug clock is stopped, CPU is "confused"
    by some bad application code and does not react anymore, after starting the application.etc.


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/
    Or you can contact us via e-mail.

  • Hi Alex,
    I checked i.mx27 datasheet and I have not found any possibility to remap or disable JTAG pins. On the board there is running Linux, which is loaded by U-Boot. I don't understand it. Unfortunately it seems to be a hardware issue...