22.3.3.5 Synchronized with Timer/Counter Type E

The TCB peripheral can be configured to use the clock (CLK_TCE) of a Timer/Counter type E (TCEn) by writing to the Clock Select (CLKSEL) bit field in the Control A (TCBn.CTRLA) register. In this setting, the TCB will count on the same clock source selected in TCEn.

Writing a ‘1’ to the Synchronize Update (SYNCUPD) bit in the Control A (TCBn.CTRLA) register restarts the TCB counter whenever the TCEn counter restarts or overflows.