TMS320F28377S: Same EPWM configuration only cause issue in specific EPWM module, part number and temperature

Hi expert,

My customer has "EPWM missing pulse issue" only happens on specific device (F28377SPTPS, which in comparision with F28377SPTPT). BTW, this issue is also closely tied with specifc EPWM module number (EPWM11) in specific conficuration "A" and temperature higher than room temperature (say, 60+ degrees C).

They now have multiple chips get this issue (estimated 5%), easy to reproduce and  this pulse missing is watched on IC pin directly.

The configuration "A" I mentioned above is:

1. TBPHS.bit.TBPHS = 0; 

2. TBCTL.bit.PHSEN = 1; 

3. TBCTL.bit.PHSDIR = 0; 

"1" + "2" or "1" + "3".

Here they have carrier works in up-down count mode. When TBPHS is not "0" issue will not happen. When phase load disabled or PHSDIR changed direction, issue will not happen.

So the first question is if this kind of configuration illegal? (SYNC load TBPHS = 0 and change counter from up to down).

Then, we'd like to know why this happen only for PTPS device?

We are testing slightly modified TI exmaple project on customer board and originally find this issue on customer board with customer SW during aging test for PTPT and PTPS device. No PTPT device ever get any issue.

Thanks

Sheldon