Hi all,
we are using phase shift / sync on 28062 PWM channels with variable frequency in up-downcount and observe missed compare events.
The missed compare events occur after changing the period+phase registers and when the compare event is nearly at the phase shift value.
F.e. the PWM counter is in upcount, period=1500, compare=999. If the phase shift is 1000, the counter may jump from 998 to 1000 due to the sync+phase, skipping the compare event (unfortunately, the compare event only occurs on ctr==compare, not ctr >= compare on upcount and ctr <= compare on downcount).
There is only a small note on page 264 of spruh18d.pdf "An EPWMxSYNCI external synchronization event can cause a discontinuity in the TBCTR count sequence. This can lead to a compare event being skipped. This skipping is considered normal operation and must be taken into account."
How can this be taken into account? Does somebody have a solution for those missed compare events?
@TI staff: Are there considerations to change the compare from ctr==compare to ctr >= compare on upcount and ctr <= compare on downcount on future devices to avoid missed compare events on sync?
