CCP/ECCP Compare Special Event

Last modified by Microchip on 2023/11/10 11:10

If the A/D module is enabled, the Special Event Trigger output starts an A/D conversion. This mode can effectively provide a 16-bit programmable period register for Timer1. The CCPx module does not assert control of the CCPx pin in this mode.

When Special Event Trigger mode is chosen (CCPxM<3:0> = 1011), the CCPx module does the following:

  • Resets Timer1
  • Starts an A/D conversion if the ADC is enabled

The Special Event Trigger output of the CCP occurs immediately upon a match between the TMR1H:TMR1L register pair and the CCPRxH:CCPRxL register pair. The TMR1H:TMR1L register pair is not reset until the next rising edge of the Timer1 clock.

1: The Special Event Trigger from the CCP module does not set interrupt flag bit TMR1IF of the PIR1 register.

2: Remove the match condition by changing the contents of the CCPRxH:CCPRxL register pair between the clock edge that generates the Special Event Trigger and the clock edge that generates the Timer1 Reset. This will preclude the Reset from occurring.