[ABANDONED] JLINK connection error

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  • [ABANDONED] JLINK connection error

    Hi,


    I working on a project using the J-Link Edu to connect through JTAG to a custom board (with the IMX6SLL implemented) with Ozone.


    It was working fine until today; I now have an error: "Could not read CP15 register. Connection failed.".
    The same behavior appears with the Dev Board from NXP, this board was connecting fine before too.
    Please find the JLink logs attached.


    Any idea of what went wrong?


    Best,


    Vincent
    [/quote]
    Files

    • log.txt

      (6.98 kB, downloaded 177 times, last: )

  • Hi,

    There is some code running on the device that prevents J-Link from halting the CPU.
    low power modes are a possible culprit.
    The error message you are seeing comes from the connect phase where J-Link temporarily halts the CPU to read out some CP15 registers to get additional information about the core + its state. Halting the core seems to fail, so the CP15 access fails.

    Unfortunately, we are not aware of any debug-related backdoor / recovery sequence that is supported by the i.MX6 series devices.

    One thing you could try to shortening the CLK pin of the QSPI flash (assuming that you boot from QSPI) to GND while powering the board, so the CPU cannot boot the bad code.
    Then you should be able to connect again.


    BR
    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,

    Thanks for your answers.

    I booting from the internal ROM, so I'll try to change the boot mode to avoid loading the bad code.

    Since I have the same behavior with the Dev Board and my custom board, is it possible that the halting problem comes from the Jlink instead of some code running?


    Vincent

  • I tried to halt the CPU through the J-Link Commander V6.94a.

    I got the following output:
    ----------------------
    J-Link>h
    Register with index 74 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 75 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 76 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 77 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 78 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 79 could not be read. Reason: CPSR indicates a non-valid CPU mode.
    Register with index 80 could not be read. Reason: CPSR indicates a non-valid CPU mode.

    ****** Error: Reading register 74 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 75 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 76 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 77 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 78 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 79 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    Reading register 80 failed: Register is temporarily not available on connected CPU (FPU disabled etc.)
    PC: (R15) = FF00000A, CPSR = 00000000 (Unknown mode, ARM)
    Current:
    R0 =00000000, R1 =00000000, R2 =00000000, R3 =00000000
    R4 =00000000, R5 =00000000, R6 =00000000, R7 =00000000
    R8 =DEADBEEF, R9 =DEADBEEF, R10=DEADBEEF, R11=DEADBEEF, R12=DEADBEEF
    R13=DEADBEEF, R14=DEADBEEF, SPSR=00000000
    USR: R8 =1008562C, R9 =1008562C, R10=1008562C, R11=1008562C, R12=1008562C
    R13=1008562C, R14=1008562C
    FIQ: R8 =1008562C, R9 =1008562C, R10=1008562C, R11=1008562C, R12=1008562C
    R13=1008562C, R14=1008562C, SPSR=1008562C
    IRQ: R13=1008562C, R14=1008562C, SPSR=1008562C
    SVC: R13=1008562C, R14=1008562C, SPSR=1008562C
    ABT: R13=1008562C, R14=1008562C, SPSR=1008562C
    UND: R13=1008562C, R14=1008562C, SPSR=1008562C

  • If everything until halting the CPU works fine, the J-Link HW is okay.
    As it was working before with your HW and then stopped working, it sounds like an application change that caused this.

    Is it possible that the same code runs on both boards?

    Reg. your boot process:
    Of course the internal ROM code runs first but it then jumps to your application which is somewhere in external memory.
    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.