21.6.9 Edge-Triggered Monostable Modes

The Edge-Triggered Monostable modes start the timer on an edge from the external Reset signal input, after the ON bit is set, and stop incrementing the timer when the timer matches the PRx period value. The following edges will start the timer:

  • Rising edge (MODE[4:0] = 10001)
  • Falling edge (MODE[4:0] = 10010)
  • Rising or Falling edge (MODE[4:0] = 10011)

When an Edge-Triggered Monostable mode is used in conjunction with the CCP PWM operation, the PWM drive goes active with the external Reset signal edge that starts the timer, but will not go active when the timer matches the PRx value. While the timer is incrementing, additional edges on the external Reset signal will not affect the CCP PWM.

Figure 21-11. Rising Edge-Triggered Monostable Mode Timing Diagram (MODE = 10001)
Note:
  1. BSF and BCF represent Bit-Set File and Bit-Clear File instructions executed by the CPU to set or clear the ON bit of TxCON. CPU execution is asynchronous to the timer clock input.