47.6.3 Host, Controller and Client Modes
In Host and Controller modes, the I2SMCC provides the host clock, the serial clock and the word select. I2SMCC_MCK, I2SMCC_CK, and I2SMCC_WS pins are outputs.
In Controller mode, the I2SMCC receiver and transmitter are disabled. Only the clocks are enabled and used by an external receiver and/or transmitter.
In Client mode, the I2SMCC receives the serial clock and the word select from an external host. I2SMCC_CK and I2SMCC_WS pins are inputs.
The mode is selected by writing I2SMCC_MRA.MODE. Since the MODE field changes the direction of the I2SMCC_WS and I2SMCC_CK pins, the I2SMCC_MRA must only be written when the I2SMCC is stopped in order to avoid unwanted glitches on the I2SMCC_WS and I2SMCC_CK pins.