Part Number: TMS320F28377S
Hi Experts
We are seeing a suspected quality issue in the F28377S related to the PWM module, This issue happens on 2 out of 200 devices, customer has run ABA test and it follows the device.
The behaviour is that when using PWM8B,
up-down counting
PRD=5556
CMPA=1024
CAU=clear
CAU=set,
The module would some how skip the CAU event. This only happens on CMPA=1024. We reproduced this using an example (AQ up-down).
In the epwm 8 interrupt, we modifiy the CMPA like below:
int i = 1022
void ISR(){
delay_us(x);
CMPA = i++;
if (i>=1025){
i=1022;
}
clear_interrupt_flags();
}What this code do is basically sweeping CMPA form 1022 to 1025. The delay is for adding variation on timing to rule out coincidents. We see the below waveforms (green): 
As you can see, there is a abnormal period when CMP = 1024.
Given the fact this only happens on 2 out of 200 devices, and ABA follows the device, it's likely a quality issue and we are planing to go through FA processs. In the meantime, cusotmer is going through process to share their demo code.
Is there any idea from the application perspective that you can share with us to find the root cause?
Regards,
Hang.
