21.3.3.3 Noise Canceler

The Noise Canceler improves noise immunity by using a simple digital filter scheme. When the Noise Filter (FILTER) bit in the Event Control (TCBn.EVCTRL) register is enabled, the peripheral monitors the event channel and keeps a record of the last four observed samples. If four consecutive samples are equal, the input is considered to be stable, and the signal is fed to the edge detector.

When enabled, the Noise Canceler introduces an additional delay of four system clock cycles between a change applied to the input and the update of the Input Compare register.

The Noise Canceler uses the system clock and is, therefore, not affected by the prescaler.