21.3 Timer/Counter Clock Sources

The Timer/Counter can be clocked by an internal synchronous or an external asynchronous clock source:

The clock source clk_T2 is by default equal/synchronous to the MCU clock, clk_I/O.

When the Asynchronous TC2 bit in the Asynchronous Status Register (ASSR.AS2) is written to '1', the clock source is taken from the Timer/Counter Oscillator connected to TOSC1 and TOSC2.

For details on asynchronous operation, see the description of the ASSR. For details on clock sources and prescaler, see Timer/Counter Prescaler.