27.3 Compare Mode

The Compare mode function described in this section is available and identical for all CCP modules.

Compare mode makes use of the 16-bit odd numbered Timer resources (Timer1, Timer3, etc.). The 16-bit value of the CCPRx register is constantly compared against the 16-bit value of the TMRx register. When a match occurs, one of the following events can occur:

  • Toggle the CCPx output and clear TMRx
  • Toggle the CCPx output without clearing TMRx
  • Set the CCPx output
  • Clear the CCPx output
  • Generate a Pulse output
  • Generate a Pulse output and clear TMRx

The action on the pin is based on the value of the MODE control bits.

All Compare modes can generate an interrupt. When MODE = ‘b0001 or ‘b1011, the CCP resets the TMRx register.

The following figure shows a simplified diagram of the compare operation.

Figure 27-2. Compare Mode Operation Block Diagram