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RTOS/TM4C1294NCPDT: XDS200 lost debug connection when USB is plugged in.

richard payne
Genius 4640 points
Part Number: TM4C1294NCPDT

Tool/software: TI-RTOS

I have USBCDC implemented into my code (TI-RTOS) for a custom board, the USB working fine without debug. I use XDS200 to TM4C device.

I note when I connect the USB plug to laptop while in debug mode (no breakpoint), it crashed and lost debug. 

The EVAL board did not crash because it use ICDI method. I use XDS200 because there no standalone ICDI module to use, only for EVAL board. 

I suspect something USBCDC halting the code and lost connection. 

Meanwhile the debug is useless due to USB connection interference, I'm open for suggestion. 

CORTEX_M4_0: GEL Output:
Memory Map Initialization Complete
CORTEX_M4_0: JTAG Communication Error: (Error -2172 @ 0x0) Unable to communicate with the debug probe. Confirm debug probe configuration and connections, reset the debug probe, and retry the operation. (Emulation package 8.0.27.9)
CORTEX_M4_0: Failed to remove the debug state from the target before disconnecting. There may still be breakpoint op-codes embedded in program memory. It is recommended that you reset the emulator before you connect and reload your program before you continue debugging

CCS 8.0

TivaWare_C_Series-2.1.4.178

tirtos_tivac_2_16_00_08

bios_6_70_01_03

  • 0
    TI__Guru*** 135355 points
    Hello Richard,

    I had some issues on a different MCU family not too unlike what you are describing, and the root cause was actually the USB hardware I was using, so if I may ask, have you tried using different USB cables? Also are you using a USB Hub or your PCs USB ports? If a hub, try without the hub as well. In my case, I had a faulty hub that caused me fits when trying to connect multiple devices. Maybe the issue is as simple to solve as changing a cable or hub...

    Aside from that non-device related idea, here are some things to check out to try and further debug what is going on as I can't find any info on that exact error code.

    Once you have USB connected, can you re-launch debug at all? Or is the error you posted occurring when trying to debug after connecting to USB?

    I presume there aren't any pins being shared by XDS200 and USB, right?

    Have you done any checks on the voltage levels of pins for JTAG before and after connecting USB? Also do you have the proper pull up/pull down resistors installed?
  • 0
    Guru 117855 points

    richard payne said:
    ... when I connect the USB plug to laptop while in debug mode (no breakpoint), it  crashed and lost debug. 

    Few more 'facts' required:

    • Kindly 'better define' what is (really) meant by 'crashed.'
    • I am unsure if you can still - "Connect Successfully' - to your custom board.     Kindly advise.
    • When you 'Connect the USB plug to laptop' - when "NOT in debug mode' - what happens?     Does everything still work?

    Is there not (some) chance that the laptop's ground - when joined to your custom board's ground (via the insertion of your USB plug to the laptop) - causes such an (unwanted) event?      And - should that same USB cable 'carry 5V  (through) to your custom board'  - while your custom board  has its own 5V supply - that's IMPROPER!     (yet likely - on your 'custom board' - is it not?)      Is that not also troubling?    

    Multiple such voltage sources should  (only rarely - and (VERY) carefully - be 'joined!')      Your 'Connection of the USB plug into the laptop' may have presented - 'either or both' -  of  the identified (potentially illegal) Ground and/or 5V (competing) joint connections!

    While your situation is (unwanted) - there are some who, 'BLOW OUT their Laptop's USB Port' - via such 'unsympathetic' connections!      My firm's focus in BLDC Motor Control & Drive has motivated our use of, "Opto-Isolated" JTAG interconnects  - which (often) prove effective against such potential distressing events - to include component damage!