28.2.3.1 Clocks

By default, the CCL is using the peripheral clock of the device (CLK_PER).

Alternatively, the CCL can be clocked by a peripheral input that is available on LUT n input line 2 (LUTn_IN[2]). This is configured by writing a '1' to the Clock Source Selection bit (CLKSRC) in the LUTn Control A register (CCL.LUTnCTRLA). The sequential block is clocked by the same clock as that of its even LUT in the LUT pair (SEQn.clk = LUT2n.clk). It is advised to disable the peripheral by writing a '0' to the Enable bit (ENABLE) in the Control A register (CCL.CTRLA) before configuring the CLKSRC bit in CCL.LUTnCTRLA.

Alternatively, the input line 2 (IN[2]) of a LUT can be used to clock the LUT and the corresponding Sequential block. This is enabled by writing a '1' to the Clock Source Selection bit (CLKSRC) in the LUTn Control A register (CCL.LUTnCTRLA).

The CCL must be disabled before changing the LUT clock source: write a '0' to the Enable bit (ENABLE) in Control A register (CCL.CTRLA).