I 2 S Features - ST STM32F102 Series Reference Manual

RM0008
2
22.2.2 I S features
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Simplex communication (only transmitter or receiver)
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Master or slave operations
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8-bit programmable linear prescaler to reach accurate audio sample frequencies (from
8 kHz to 48 kHz)
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Data format may be 16-bit, 24-bit or 32-bit
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Packet frame is fixed to 16-bit (16-bit data frame) or 32-bit (16-bit, 24-bit, 32-bit data
frame) by audio channel
● Programmable clock polarity (steady state)
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Underrun flag in slave transmission mode and Overrun flag in reception mode (master
and slave)
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16-bit register for transmission and reception with one data register for both channel
sides
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Supported I
–
–
–
–
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Data direction is always MSB first
● DMA capability for transmission and reception (16-bit wide)
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Master clock may be output to drive an external audio component. Ratio is fixed at
256 × F
2
S protocols:
2
I S Phillips standard
MSB-Justified standard (Left-Justified)
LSB-Justified standard (Right-Justified)
PCM standard (with short and long frame synchronization on 16-bit channel frame
or 16-bit data frame extended to 32-bit channel frame)
(where F is the audio sampling frequency)
S S
Serial peripheral interface (SPI)
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