19.4.2.6.1 BCLK/SCKx and LRCK Generation

BCLK and LRCK generation is a key requirement in Host mode. The frame frequency of SCKx and LRCK is defined by the MODE[32,16] bits (SPIxCON1[11:10]). When the frame is 64 bits, SCKx is 64 times the frequency of LRCK. Similarly, when the frame is 32 bits, SCKx is 32 times the frequency of LRCK. The frequency of SCKx must be derived from the toggling rate of LRCK and the frame size.

For example, to sample 16-bit channel data at 8 kHz with SPICLK = 36.864 MHz, set the SPIxBRG register to 0x47 to generate an 8 kHz LRCK.