Serial peripheral interface/ inter-IC sound (SPI/I2S) RM0402
852/1163 RM0402 Rev 6
26.7 SPI and I
2
S registers
The peripheral registers can be accessed by half-words (16-bit) or words (32-bit). SPI_DR
in addition by can be accessed by 8-bit access.
Refer to Section 1.2 for a list of abbreviations used in register descriptions.
The peripheral registers can be accessed by half-words (16 bits) or words (32 bits).
26.7.1 SPI control register 1 (SPI_CR1) (not used in I
2
S mode)
Address offset: 0x00
Reset value: 0x0000
1514131211109876543210
BIDI
MODE
BIDI
OE
CRC
EN
CRC
NEXT
DFF
RX
ONLY
SSM SSI
LSB
FIRST
SPE BR [2:0] MSTR CPOL CPHA
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bit 15 BIDIMODE: Bidirectional data mode enable
This bit enables half-duplex communication using common single bidirectional data line.
Keep RXONLY bit clear when bidirectional mode is active.
0: 2-line unidirectional data mode selected
1: 1-line bidirectional data mode selected
Note: This bit is not used in I
2
S mode
Bit 14 BIDIOE: Output enable in bidirectional mode
This bit combined with the BIDIMODE bit selects the direction of transfer in bidirectional
mode
0: Output disabled (receive-only mode)
1: Output enabled (transmit-only mode)
Note: In master mode, the MOSI pin is used while the MISO pin is used in slave mode.
This bit is not used in I
2
S mode.
Bit 13 CRCEN: Hardware CRC calculation enable
0: CRC calculation disabled
1: CRC calculation enabled
Note: This bit should be written only when SPI is disabled (SPE = ‘0’) for correct operation.
It is not used in I
2
S mode.
Bit 12 CRCNEXT: CRC transfer next
0: Data phase (no CRC phase)
1: Next transfer is CRC (CRC phase)
Note: When the SPI is configured in full-duplex or transmitter only modes, CRCNEXT must be
written as soon as the last data is written to the SPI_DR register.
When the SPI is configured in receiver only mode, CRCNEXT must be set after the
second last data reception.
This bit should be kept cleared when the transfers are managed by DMA.
It is not used in I
2
S mode.
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