[SOLVED] Cannot connect to target after watchdog reset -Vybrid

  • [SOLVED] Cannot connect to target after watchdog reset -Vybrid

    Hello,
    While debugging the M4 side on VF6xx_M4, if the M4 watchdog reset happens and system restarts, I cannot connect to it with JLink unless I power cycle the board.
    This is both with JLinkGDBServer and JLinkExe.

    JLinkExe tells me
    ****** Error: Vybrid Cortex-M4 (connect): Could not power up debug port.

    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01

    ****** Error: Vybrid Cortex-M4 (connect): Could not power up debug port.

    Cannot connect to target.
    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01
    TotalIRLen = 4, IRPrint = 0x01

    GDB server tells me

    SEGGER J-Link GDB Server V6.10c Command Line Version

    JLinkARM.dll V6.10c (DLL compiled Sep 28 2016 18:30:23)

    -----GDB Server start settings-----
    GDBInit file: none
    GDB Server Listening port: 2331
    SWO raw output listening port: 2332
    Terminal I/O port: 2333
    Accept remote connection: localhost only
    Generate logfile: off
    Verify download: on
    Init regs on start: on
    Silent mode: off
    Single run mode: on
    Target connection timeout: 0 ms
    ------J-Link related settings------
    J-Link Host interface: USB
    J-Link script: none
    J-Link settings file: none
    ------Target related settings------
    Target device: VF6xx_M4
    Target interface: JTAG
    Target interface speed: 1000kHz
    Target endian: little

    Connecting to J-Link...
    J-Link is connected.
    Firmware: J-Link V10 compiled Sep 1 2016 18:29:58
    Hardware: V10.00
    S/N: xxxxxxxxxxxxxx
    Feature(s): RDI, FlashBP, FlashDL, JFlash, GDB
    Checking target voltage...
    Target voltage: 3.33 V
    Listening on TCP/IP port 2331
    Connecting to target...ERROR: Vybrid Cortex-M4 (connect): Could not power up debug port.

    ERROR: Could not connect to target.
    Target connection failed. GDBServer will be closed...Restoring target state and closing J-Link connection...
    Shutting down...

    The system reset pin does not help, need power cycle. Why does this happen?

    The post was edited 1 time, last by v01d ().

  • Hi,

    Sounds like the watchdog reset also resets the debug logic which results in J-Link loosing the connection to the device. Furthermore, it seems like after a watchdog reset occurred, the device enters a wired state where a power-on-reset is required to bring it back into a good state. We can check this again but there are some devices out there which behave similar.


    Best regards
    Erik
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  • SEGGER - Erik wrote:

    Hi,

    Sounds like the watchdog reset also resets the debug logic which results in J-Link loosing the connection to the device. Furthermore, it seems like after a watchdog reset occurred, the device enters a wired state where a power-on-reset is required to bring it back into a good state. We can check this again but there are some devices out there which behave similar.


    Best regards
    Erik
    Thanks for answering this.
    So basically Vybrid's are not debug'able with watchdogs enabled really.. Well if you hit the timeout. (which may happen as you debug.. )
    :thumbdown: