40.6.2.4 Counter Mode
The counter mode is selected by the Mode bit group in the Control A register
(CTRLA.MODE). By default, the counter is enabled in the 16-bit counter resolution. Three
counter resolutions are available:
- COUNT8 – The 8-bit TC has its own Period Value and Period Buffer Value registers (PER and PERBUF).
- COUNT16 – 16-bit is the default counter mode. There is no dedicated period register in this mode.
- COUNT32 – 32-bit mode is achieved by
pairing two 16-bit TC peripherals. TC0 is paired with TC1, and TC2 is paired with
TC3. TC4 is paired with TC5 and TC6 with TC7 for the COUNT32 mode.
When paired, the TC peripherals are configured using the registers of the even-numbered TC (TC0, TC2, TC4 or TC6, respectively).
The TC bus clocks (PB1_CLK) for both host and client TCs need to be enabled.
The odd-numbered partner (TC1, TC3, TC5 or TC7 respectively) acts as a client TC, and the Client bit in the Status register (STATUS.CLIENT) is set. The register values of a client TC will not reflect the registers of the 32-bit counter. Writing to any of the client registers will not affect the 32-bit counter. Normal access to the client COUNT and CCx registers is not allowed.