Dear Joe,
Thank you for your input. But in this case the ISR still has to wait for a certain amount of time until 5 pulses have completed and when it hits the RETI then it get out of there. I agree that it will use less MCU resource but timewise I think it's still the same. Let's say TM2 is used for compare and when the value is matched then Int is requested. Assuming that TM1 is preload and ready to go it just waits for the Int from CM0 to kick in. Once it kicks in, it will toggle the port pin as 5 times. When it's done then get out of the ISR. Therefore, I don't see that I can save anything here unless I change the number of pulses.
In this application I have to monitor the firing angle constantly to deliver a constant current to the Motor's Field. I can't afford to miss any cycle of AC voltage line, otherwise motor will hum and creat resonance back to the transformer.


Dear Russell
Yes, the problem is worst when the firing angle of both set is the same or almost the same.


Yes, I thought of that as I already purchased a kit from Silabs.

PS:Russell, you seem to have a lots of experience with Thyristor control don't you. If so, I hope that you wouldn't mind to share your experience with us. Thanks

BTW: Thank you all for your kind inputs/suggestions. I solved my problem. I just set the IP for the CM1 higher than CM0 then everything is good. I feel better now.

Regards,
T.L