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TM4C1294NCPDT: Problem in Accessing the Tiva Controller.

Bharath Raj
Intellectual 265 points
Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: UNIFLASH

Hi,

I am currently working on tm4c1294ncpdt. i have problem related to dumping or erasing the program from the controller. I have dumped one code on controller, later if i try to erase the code from controller its not erasing (cant even dump). I am using keil software and ulink2 debugger. I have tried with all clock levels for debugger. The code which i used first had logic related to UDP. Now the green LED of RJ45 connector is continuously blinking with higher speed. I am not able to access the controller now. Is there any way to erase the code which is on controller ? Please help me in identifying the problem and resolving it as soon as possible.  

  • 0
    Guru 13040 points

    Bharath,

    Yes best bet is to download LMFlash or UniFlash from TI's web site, and use the Port Unlock option.

    If you don't have a probe compatible with these programs' unlock feature, this thread explains how to do the unlocking via command mode on CCS:

    e2e.ti.com/.../475655

    Regards

    Bruno

  • 0 in reply to Bruno Saraiva
    Intellectual 265 points
    Bruno,
    i tried to unlock. Plz check the below

    Status: CORTEX_M4_0: Starting Debug Port Unlock operation...
    Status: CORTEX_M4_0: Initial Unlock completed, please release reset button and press the "Finish Unlock" button in the Flash options to complete the operation...
    Status: CORTEX_M4_0: Power cycle the board to complete the unlock procedure.

    But i don think its doing any changes cause i am not able to dump or erase the controller. Plz tell me whether i am missing anything?
  • 0 in reply to Bharath Raj
    Guru 13040 points
    Bharath,
    The port unlocker is a bit tricky... When it says that procedure was complete, it does not necessarily mean it worked.
    First, as an act of despair, I'd try the procedure a couple of times more, paying close attention to the sequence of power cycle.
    But if that does not work, you will need to check some less likely stuff:
    - Old "Microsoft" problem solving: restart your PC - seriously, it is rare but sometimes the debugger stop working.
    - Check all the voltages on your MCU - are you sure it is powered properly?
    - Is your reset line properly routed? Might it be stuck low?
    - Did you try programming other boards with the same setup?
    - Just to make sure the connection is fine, can you READ the memory with UniFlash?
    I can't seem to think anything else that you are missing...
    Bruno
  • 0 in reply to Bruno Saraiva
    Guru 117855 points

    Here some additional thoughts:

    • Untold is the quality of your MCU board - is it "factory" or your own "home-brew?"
    • Single-Board anomalies "plague" those charged w/diagnostics.   Have you a 2nd (identical) board?   (always wise to acquire 2, even 3 such boards to avoid "single board plague!)
    • Avoid use of your program for now - always (and only) START w/vendor supplied, "Known good" example code/program.   Two "horrors" are enabled when you "download" (NOT dump) your own code: a) you may overwrite any of the 4 dedicated JTAG signal lines (usually PC0-PC3) and/or b) you may incorrectly match the external crystal frequency w/the System Clock Set function.   Either misstep will yield the unpleasantness you present here.   Does your code impact the two key/critical areas - just described?

    Your best bet is to attempt "download" of a (proper) vendor supplied program to a FRESH (different) board.   Note the success or failure of that attempt.   If your board is "home-brew" - Pandora's box of potential issues enters - you've thus created the condition where, "Everything is SUSPECT!"   (new board, new code etc.)   If home-brew - your saving of the size/cost/effort "penalty" by the use of 4 JTAG pull-up resistors - instead relying upon (too high value) internal MCU resistors - yields (most always) a "less than robust" JTAG interface.   (works (some) of the time - but NOT when most needed! (i.e. real-world w/noise))

    As vendor persists in, "Failing to properly guide posters" none of these vital facts were included - raising "wear/tear" on humble (outside) diagnostic staff...   (yet also upon skilled vendor staff - who should require this data to make best/brightest analysis...)