TM4C123GH6PM: unstable MCU power performance

Hi,

  Can you elaborate what is not working? Is it that you cannot connect to the device using the debugger? Or is it that you cannot download new firmware?  Or the application firmware does not run after loaded. Please be specific.

  Personally, I have not heard of a forum reporting that a device first works for a few times and then stop working and finally after waiting for a few more days the device works again. The only thing I can think of is temperature related but you will need to do some experiments to isolate the problem. This is what I will suggest you do.:

  - Does it fail more quickly if you raise the operating environment temperature? You will need to heat up the board using a heat gun or use some type of ThermalStream equipment to raise the DUT temperature.

  - Does it fail less quickly or stop failing  if you reduce the operating environment temperature? You will need to cool down the device using some type of ThermalStream equipment.

  - Do a ABA swap test. 

The A-B-A Swap Method is a simple cross check test, which can confirm the observed issue is not systemic.

• A-B-A Swap Method
  (1) Remove the suspected component (A) from the original failing board.
  (2) Replace the suspected component (A) with a known good component (B) and check if the original board now works properly.
  (3) Mount the suspected component (A) to a known good board and see if the same failure occurs on the good board.

Step 3 is important because it helps us to exclude any possibility that the issue is caused by a systemic issue or the interaction of multiple slightly bad components on a good board.

 Once you have the results and if you prove 100% it is a MCU problem then you can contact the local TI office for quality return process.