22.2.1 Block Diagram

Figure 22-1. TCB Block Diagram

The timer/counter can be clocked from the Peripheral Clock (CLK_PER), from a 16-bit Timer/Counter type E (CLK_TCEn), or the Event System (EVSYS).

Figure 22-2. Timer/Counter Clock Logic

The Clock Select (CLKSEL) bit field in the Control A (TCBn.CTRLA) register selects one of the prescaler outputs directly or an event channel as the clock (CLK_TCB) input.

Setting the timer/counter to use the clock from a TCEn allows the timer/counter to run in sync with that TCEn.

Using the EVSYS, any event source, such as an external clock signal on any I/O pin, may be used as the counter clock input or a control logic input. When using an event action controlled operation, set the clock selection to use an event channel as the counter input.