ST STM32G473 User Manual

Serial peripheral interface / integrated interchip sound (SPI/I2S) RM0440
1772/2126 RM0440 Rev 4
Figure 607 presents the communication clock architecture. The I2SxCLK clock is provided
by the reset and clock controller (RCC) of the product. The I2SxCLK clock can be
asynchronous with respect to the SPI/I2S APB clock.
Warning: In addition, it is mandatory to keep the I2SxCLK frequency
higher or equal to the APB clock used by the SPI/I2S block. If
this condition is not respected, the SPI/I2S does not work
properly.
The audio sampling frequency may be 192 kHz, 96 kHz, 48 kHz, 44.1 kHz, 32 kHz,
22.05 kHz, 16 kHz, 11.025 kHz or 8 kHz (or any other value within this range).
In order to reach the desired frequency, the linear divider needs to be programmed
according to the formulas below:
For I
2
S modes:
When the master clock is generated (MCKOE in the SPIx_I2SPR register is set):
When the master clock is disabled (MCKOE bit cleared):
CHLEN = 0 when the channel frame is 16-bit wide and,
CHLEN = 1 when the channel frame is 32-bit wide.
For PCM modes:
When the master clock is generated (MCKOE in the SPIx_I2SPR register is set):
When the master clock is disabled (MCKOE bit cleared):
CHLEN = 0 when the channel frame is 16-bit wide and,
CHLEN = 1 when the channel frame is 32-bit wide.
Where F
S
is the audio sampling frequency, and F
I2SxCLK
is the frequency of the kernel clock
provided to the SPI/I2S block.
Fs
FI2SxCLK
256 2(( I2SDIV)× ODD)+×
--------------------------------------------------------------------------------------------------------
=
Fs
FI2SxCLK
32 CHLEN 1)+(× 2(( I2SDIV)× ODD)+×
--------------------------------------------------------------------------------------------------------------------------------------------------------------
=
Fs
FI2SxCLK
128 2(( I2SDIV)× ODD)+×
--------------------------------------------------------------------------------------------------------
=
Fs
FI2SxCLK
16 CHLEN 1)+(× 2(( I2SDIV)× ODD)+×
--------------------------------------------------------------------------------------------------------------------------------------------------------------
=

ST STM32G473 Specifications

General

Brand	ST
Model	STM32G473
Category	Microcontrollers
Language	English