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. TC(2n) is paired with TC(n+1).
When paired, the TC peripherals are configured using the registers of the even-numbered TC (TC0 or TC2, respectively).
The TC bus clocks (PB1_CLK) for both host and client TCs need to be enabled.
The odd-numbered partner (TC1 or TC3, respectively) will act as a client, and the Client bit in the Status register (STATUS.SLAVE) will be set. The register values of a client 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.