42.6.3.4.1 Re-trigger Software Command or Event Action
A re-trigger command can be issued from software by using PDEC Command bits in Control B Set register (CTRLBSET.CMD = RETRIGGER).
When the re-trigger command is detected during counting operation, the counter will be reloaded or cleared, depending on the counting direction (DIR). If the re-trigger command is detected when the counter is stopped, the counter will resume counting operation from the value in the COUNT register.