29.5.3 Clocks

The clock for the I²S bus interface (CLK_I2S_APB) is generated by the Power Manager. This clock is disabled at reset, and can be enabled in the Power Manager. It is recommended to disable the I²S before disabling the clock, to avoid freezing the I²S in an undefined state.

There are two generic clocks, GCLK_I2S_0 and GCLK_I2S_1, connected to the I²S peripheral, one for each I²S clock unit. The generic clocks (GCLK_I2S_n, n=0..1) can be set to a wide range of frequencies and clock sources. The GCLK_I2S_n must be enabled and configured before use.

The GCLK_I2S_n clocks must be enabled and configured before triggering Software Reset, so that the logic in all clock domains can be reset.

The generic clocks are only used in Host mode and Controller mode. In Host mode, the clock from a single clock unit can be used for both Serializers to handle synchronous transfers, or a separate clock from different clock units can be used for each Serializer to handle transfers on non-related clocks.