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RM0440 Rev 4 1763/2126

RM0440 Serial peripheral interface / integrated interchip sound (SPI/I2S)

1791

For all data formats and communication standards, the most significant bit is always sent

first (MSB first).

The I

S interface supports four audio standards, configurable using the I2SSTD[1:0] and

PCMSYNC bits in the SPIx_I2SCFGR register.

S Philips standard

For this standard, the WS signal is used to indicate which channel is being transmitted. It is

activated one CK clock cycle before the first bit (MSB) is available.

Figure 588. I

S Philips protocol waveforms (16/32-bit full accuracy)

Data are latched on the falling edge of CK (for the transmitter) and are read on the rising

edge (for the receiver). The WS signal is also latched on the falling edge of CK.

Figure 589. I

S Philips standard waveforms (24-bit frame)

This mode needs two write or read operations to/from the SPIx_DR register.

• In transmission mode:

If 0x8EAA33 has to be sent (24-bit):

MS19591V1

Can be 16-bit or 32-bit

MSB

MSBLSB

Channel left

Channel

right

transmission reception

MS19592V1

Transmission Reception

24-bit data

MSB

LSB

Channel left 32-bit

Channel right

8-bit remaining 0 forced

ST STM32G471 User Manual

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