22 Capture/Compare/PWM Module

The Capture/Compare/PWM module is a peripheral that allows the user to time and control different events, and to generate Pulse-Width Modulation (PWM) signals. In Capture mode, the peripheral allows the timing of the duration of an event. The Compare mode allows the user to trigger an external event when a predetermined amount of time has expired. The PWM mode can generate Pulse-Width Modulated signals of varying frequency and duty cycle.

This family of devices contains two standard Capture/Compare/PWM modules (CCP1 and CCP2). Each individual CCP module can select the timer source that controls the module. Each module has an independent timer selection which can be accessed using the CxTSEL bits in the CCPTMRS register. The default timer selection is TMR1 when using Capture/Compare mode and T2TMR when using PWM mode in the CCPx module.

It should be noted that the Capture/Compare mode operation is described with respect to TMR1 and the PWM mode operation is described with respect to T2TMR in the following sections.

The Capture and Compare functions are identical for all CCP modules.

Important:
  1. In devices with more than one CCP module, it is very important to pay close attention to the register names used. A number placed after the module acronym is used to distinguish between separate modules. For example, the CCP1CON and CCP2CON control the same operational aspects of two completely different CCP modules.
  2. Throughout this section, generic references to a CCP module in any of its operating modes may be interpreted as being equally applicable to CCPx module. Register names, module signals, I/O pins, and bit names may use the generic designator ‘x’ to indicate the use of a numeral to distinguish a particular module, when required.