26.3 PWM Period

The PWM period is specified by the TxPR register. The PWM period can be calculated using the formula of Equation 26-1. It is required to have F_OSC/4 as the selected clock input to the timer for correct PWM operation.

Equation 26-1. PWM Period

$P W M P e r i o d = [(T 2 P R) + 1] • 4 • T o s c • (T M R 2 \Pr e s c a l e V a l u e)$

Note: T_OSC = 1/F_OSC

When TxTMR is equal to TxPR, the following three events occur on the next increment cycle:

TxTMR is cleared
The PWM output is active (Exception: When the PWM duty cycle = 0%, the PWM output will remain inactive)
The PWMxDCH and PWMxDCL register values are latched into the buffers

Important: The Timer2 postscaler has no effect on the PWM operation.