25.4.5 Asynchronous Clock Counter Mode

When TxCON.TCS = 1, TxCON.ON = 1 and TxCON.TSYNC = 0, the timer increments on every rising edge of the applied external clock signal. The timer counts up to a match value preloaded in the respective period register, then rolls over and continues. This incrementing sequence repeats until the timer is disabled (refer to Figure 25-5).

Figure 25-5. Asynchronous External Clock Mode Timing Diagram

When the timer is configured for asynchronous operation and the CPU goes into Idle mode with TxCON.SIDL = 1 or Sleep, the timer continues incrementing.