AT32F421
Series Reference Manual
2022.11.11
Page 159
Rev 2.02
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Master device transmission
─
Master device reception
Programmable clock polarity
Programmable clock frequency (8 KHz to 192 KHz)
Programmable data bits (16 bit, 24 bit, 32 bit)
Programmable channel bits (16 bit, 32 bit)
Programmable audio protocol
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I
2
S Philips standard
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MSB-aligned standard (left-aligned)
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LSB-aligned standard (right-aligned)
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PCM standard (long or short frame)
DMA transfer
Main peripheral clock with a fixed frequency of 256x Fs (audio sampling frequency)
13.3.2 Operation mode selector
The SPI, used as I
2
S selector, offers multiple operation modes for selection, namely, slave device
transmission, slave device reception, master device transmission and master device reception. This is
done by software configuration.
Slave device transmission:
Set the I2SMSEL bit, and OPERSEL[1:0] =00, the I2S will work in slave device transmission mode.
Figure 13-14 I
2
S slave device transmission
I2S master
CK
SD
WS
I2S slave
CK
SD
WS
Slave device reception:
Set the I2SMSEL bit, and OPERSEL[1:0]=01, the I
2
S will work in slave device reception mode.
Figure 13-15 I
2
S slave device reception
I2S master
CK
SD
WS
I2S slave
CK
SD
WS