18.6.1 Compare Output Mode and Waveform Generation

The waveform generator uses the TCCR0A.COM0x[1:0] bits differently in Normal, CTC, and PWM modes. For all modes, setting the TCCR0A.COM0x[1:0]=0x0 tells the waveform generator that no action on the OC0x register is to be performed on the next compare match. Refer to the descriptions of the output modes.

A change of the TCCR0A.COM0x[1:0] bits state will have effect at the first compare match after the bits are written. For non-PWM modes, the action can be forced to have immediate effect by using the TCCR0C.FOC0x strobe bits.