35.6.2.4 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, TC2 is paired
with TC3. TC4, TC5, TC6 and TC7 cannot be paired.
When paired, the TC peripherals are configured using the registers of the even-numbered TC. The TC bus clocks (CLK_TCx_APB) for both Host and Client TCs need to be enabled.
The odd-numbered partner will act as a Client, and the Client bit in the Status register (STATUS.Client) 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.