Input Blanking

Input blanking functionality are masking out the input Events for a programmable time in a selectable part of the TCD cycle. Input blanking can be used to mask out "false" input Events that are triggered right after changes on the outputs.

To enable input blanking, write 0x1 to the Delay Select bit field in the Delay Control register (DLYSEL in TCD.DLYCTRL). The trigger source is selected by the Delay Trigger bit field (DLYTRIG in TCD.DLYCTRL).

Input blanking uses the Delay clock: after a trigger, a counter is counting up until the Delay Value (DLYVAL in TCD.DLYVAL) is reached before input blanking is turned off. The TCD delay clock is a prescaled version of the Synchronization clock. The division factor is set by the Delay Prescaler bit field in the Delay Control register (DLYPRESC in TCD.DLYCTRL). The duration of the input blanking is given by

tBLANK=DLYPRESC_division_factor×DLYVALfCLK_TCD_SYNC

Input blanking is using the same logic as the programmable output Event. For this reason it is not possible to use both at the same time.