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USB COM Port for Tiva Launchpad always disconnect at Windows 10?

Markel Robregado
Guru 86605 points
Other Parts Discussed in Thread: CC3100

Hi,

Just today, I have observed my COM Port for Tiva Connected Launchpad to be always disconnecting and then reconnecting. So, during CCS debug I get this error message below. Even if I stop debugging, I observed at Tera Term to always disconnecting and then reconnecting at the COM Port for Tiva Connected Launchpad. I have set all needs to be set at Windows 10 for the USB to be not suspended or powered off. What could be causing this and how do I solve this problem?

Device Setup: Tiva Connected Launchpad + CC3100 BP + Sensor Hub BP powered using USB

Program: Send BMP180 Sensor Data to Samsung Artik Cloud, uart_echo

OS: Windows 10

CCS Version: Version: 6.2.0.00050 

CCS Error Message:

CORTEX_M4_0: Error: Connection with the target was unexpectedly lost.
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.

Further troubleshooting steps:

Using LM Flash Programmer I erase entire flash contents, and with just the Tiva Connected Launchpad + Sensor Hub BP, I debug run the BMP180 Example Program, and it worked for a long time.

But, why above setup causes the COM port for Tiva Connected Launchpad to always disconnecting and reconnecting? The program did not go to FaultISR().

Is it possible that the cause is lacking of memory caused by some operation in the program?

- kel

  • 0
    TI__Guru**** 244380 points
    Hello Kel

    Couple of points to consider.

    1. The CCS Error message is not COM port but DEBUG port.
    2. Is the current requirement for the entire setup been calculated and seen to meet the USB bus power? Did you try using an external power source?
  • 0 in reply to Amit Ashara
    Guru 86605 points

    Amit Ashara said:
    1. The CCS Error message is not COM port but DEBUG port.

    Yes, you are right. 

    Amit Ashara said:
    2. Is the current requirement for the entire setup been calculated and seen to meet the USB bus power? Did you try using an external power source?

    I have not done any current requirement calculations, but have used the same setup, Tiva Connected Launchpad + CC3100 BP + Sensor Hub BP to send data to Exosite, and it worked without problems for an entire day. 

    I will try an external power source.

    - kel

  • 0 in reply to Markel Robregado
    Guru 26105 points

    Hi,

    Look for Microsoft's USBView.exe utility, to tell you: a) your USB port current capability and b) the current drawn.

    USB ports are in versions of 100mA, 500mA.

    Also, ICDI does not support too many breakpoints, Amit can tell you the latest figures about that.

  • 0 in reply to Petrei
    TI__Guru**** 244380 points
    Hello Petrei

    I still think the number of breakpoints are still the same. There has been no change made.
  • 0 in reply to Petrei
    Guru 86605 points
    Hi Petrei,

    Using USBView the current is 250 Ma. I will try a external power supply, maybe 5V 1A.

    Configuration Descriptor:
    wTotalLength: 0x0074
    bNumInterfaces: 0x04
    bConfigurationValue: 0x01
    iConfiguration: 0x00
    bmAttributes: 0x80 (Bus Powered )
    MaxPower: 0x7D (250 Ma)

    - kel
  • 0 in reply to Markel Robregado
    Guru 47900 points

    Markel Robregado said:
    MaxPower: 0x7D (250 Ma)

    I know nothing of USBView and its method of representing power - yet 0x7D is less than half of "8 bit, full scale" (255) thus (may) be suspect.   In fact - 0x7D translates to 125 decimal - but again - USBView's method of representing power is unknown by this reporter...

    Thanks to Petrei for the mention of USBView - it seems useful for multiple tasks...