29.7.1 Period Interrupt
The period interrupt occurs when the PWMx timer value matches the PR value, thereby also resetting the PWMx timer. Refer to Figure 29-2 for a timing example. The period interrupt is indicated with the PWMxPIF flag bit in one of the PIR registers and is set whether or not the interrupt is enabled. This flag must be reset by software. The PWMxPIF interrupt is enabled with the PWMxPIE bit in the corresponding PIE register.