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: This mode is achieved
by pairing two 16-bit TC peripherals. TCn is paired with TCn+1. TC2 does not support 32-bit resolution.
When paired, the TC peripherals are configured using the registers of
the even-numbered TC. The odd-numbered partner 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.