Serial peripheral interface / inter-IC sound (SPI/I2S)
RM0365
957/1080
DocID025202 Rev 7
Bit 3
CKPOL
: Inactive state clock polarity
0: I
2
S clock inactive state is low level
1: I
2
S clock inactive state is high level
Note: For correct operation, this bit should be configured when the I
2
S is disabled.
It is not used in SPI mode.
The bit CKPOL does not affect the CK edge sensitivity used to receive or transmit the SD and
WS signals.
Bits 2:1
DATLEN
: Data length to be transferred
00: 16-bit data length
01: 24-bit data length
10: 32-bit data length
11: Not allowed
Note: For correct operation, these bits should be configured when the I
2
S is disabled.
They are not used in SPI mode.
Bit 0
CHLEN
: Channel length (number of bits per audio channel)
0: 16-bit wide
1: 32-bit wide
The bit write operation has a meaning only if DATLEN = 00 otherwise the channel length is fixed to
32-bit by hardware whatever the value filled in.
Note: For correct operation, this bit should be configured when the I
2
S is disabled.
It is not used in SPI mode.