• State
  • Locked Locked
  • Replies 7 replies
  • Subscribers 33 subscribers
  • Views 2577 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

EK-TM4C123GXL: Couldn't find an Cortex-M device in the JTAG chain

Diyala Erekat
Prodigy 30 points

Part Number: EK-TM4C123GXL
Other Parts Discussed in Thread: UNIFLASH

Hi, 

The launchpad was working perfectly fine and then, out of a sudden, it stopped. 

When I ever I connected to the computer, the LED on the launchpad turns on, but there is no sound of a USB device Connected/Disconnected coming from the PC as it was before. I pressed the reset the button for 10 seconds hoping to wipe the code inside, that didn't work. I changed the USB cable couple of times, that didn't work either.  I am using Keil uVision 4.

Thats the error I am getting:

And thats the view from Options Target:

  • 0
    Guru 13040 points
    Hello,
    Did you try to download UniFlash, and use the UNLOCK procedure there? It might help.
    Bruno
  • 0 in reply to Bruno Saraiva
    TI__Guru**** 191886 points
    Hello,
    As suggested by Bruno to use Uniflash, you can also use LM Flash Programmer www.ti.com/.../lmflashprogrammer.
  • 0
    Guru 117855 points

    Diyala Erekat said:
    The launchpad was working perfectly fine and then, out all of a sudden, it stopped. 

    True that - we are sure.     Never would the, "Repurposing of JTAG signal lines" and/or the "flawed setting of System Clock" be admitted to the mix.

    Unstated - as always - the last actions by poster PRIOR to the "demise" of his board.

    Prevention so much exceeds (any) cure!     (thus should most always - be noted...)

  • 0 in reply to cb1_mobile
    Prodigy 30 points

    Very helpful indeed. 

    You want to know what happened exactly, sure I will tell you. 

    No, there was no repurposing of JTAG signal lines nor any flawed setting of System Clock. 

    The clock is initialized as follows:

    void SysTick_Init(){ // working on 80Mhz
      NVIC_ST_CTRL_R = 0; // disables SysTick during setup
      NVIC_ST_CURRENT_R = 0; // Clears any write to current
      NVIC_ST_RELOAD_R = 800000-1; //10ms and the counter rolls every 10 ms
      NVIC_SYS_PRI3_R = (NVIC_SYS_PRI3_R&0x00FFFFFF)|0x40000000; //with priority 2
      NVIC_ST_CTRL_R = 0x07; // enable SysTick with core clock and interrupts
    }

    The system that I was testing had 8 buttons as digital inputs and a Nokia 5110 LCD Display. All of the sudden, it stopped working. I don't know exactly what went wrong, therefore I am asking. I didn't mention the previous "actions" prior to the demise of my board as to me; a newbie, it sounded normal/not dangerous.

    So instead of being condescending, it would have been great if you offered helpful information instead.  

  • 0 in reply to Charles Tsai
    Prodigy 30 points
    The PC doesn't recognize the launchpad anymore, so even Flash Programmer is no help in this case. Thanks though
  • 0 in reply to Diyala Erekat
    Guru 117855 points

    Diyala Erekat said:
    it would have been great if you offered helpful information instead.

    By FAR - the two leading causes of such, "Unintentional Lockout"are those I listed.     Many would find that info helpful - to include you - with a cooler head.

    Beyond those two - hard to say - perhaps those 8 buttons admitted ESD - yet that's purely a guess.

    On rare occasion the PC - or the USB cable can cause/contribute to such "lock-out."    I'd switch cables first - try w/a 2nd PC should that fail.

  • 0 in reply to Diyala Erekat
    TI__Guru**** 191886 points

    Hi,

     In case you have not yet tried, can you please restart your PC/Windows and change the USB cable? I happened to swap the USB cable one time and got an unrecognized LaunchPad to be recognized again. This is not to say this the cause of your problem. It is just something to try.  Same for restarting the PC. 

     Please also go to Windows device manager and see if you see below when you plug in the LaunchPad.