CS12 CS11 CS10 Description
0____0____0____No clock source (Timer/Counter stopped).
0____0____1____clkI/O/1 (No prescaling)
0____1____0____clkI/O/8 (From prescaler)
0____1____1____clkI/O/64 (From prescaler)
1____0____0____clkI/O/256 (From prescaler)
1____0____1____clkI/O/1024 (From prescaler)
1____1____0____External clock source on T1 pin. Clock on falling edge.
1____1____1____External clock source on T1 pin. Clock on rising edge.