RM0440 Rev 4 1779/2126
RM0440 Serial peripheral interface / integrated interchip sound (SPI/I2S)
1791
synchronization is lost, the following steps are required to recover from this state and
resynchronize the external master device with the I2S slave device:
1. Disable the I2S.
2. Enable it again when the correct level is detected on the WS line (WS line is high in I
2
S
mode or low for MSB- or LSB-justified or PCM modes.
Desynchronization between master and slave devices may be due to noisy environment on
the CK communication clock or on the WS frame synchronization line. An error interrupt can
be generated if the ERRIE bit is set. The desynchronization flag (FRE) is cleared by
software when the status register is read.
39.7.9 DMA features
In I
2
S mode, the DMA works in exactly the same way as it does in SPI mode. There is no
difference except that the CRC feature is not available in I
2
S mode since there is no data
transfer protection system.
39.8 I2S interrupts
Table 360 provides the list of I2S interrupts.
Table 360. I2S interrupt requests
Interrupt event Event flag Enable control bit
Transmit buffer empty flag TXE TXEIE
Receive buffer not empty flag RXNE RXNEIE
Overrun error OVR
ERRIEUnderrun error UDR
Frame error flag FRE
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