GD32F20x User Manual
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Figure 21-27. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=0)
I2S_CK
I2S_SD
8-bit 0
frame 1 (channel left)
frame 2 (channel right)
I2S_WS
24-bit data
MSB
LSB
Figure 21-28. LSB justified standard timing diagram (DTLEN=01, CHLEN=1, CKPL=1)
I2S_CK
I2S_SD
8-bit 0
frame 1 (channel left)
frame 2 (channel right)
I2S_WS
24-bit data
MSB
LSB
When the packet type is 24-bit data packed in 32-bit frame, two write or read operations to or
from the SPI_DATA register are needed to complete a frame. In transmission mode, if a 24-
bit data D [23:0] is going to be sent, the first data written to the SPI_DATA register should be
a 16-bit data. The higher 8 bits of the 16-bit data can be any value and the lower 8 bits should
be D [23:16]. The second data written to the SPI_DATA register should be D [15:0]. In
reception mode, if a 24-bit data D [23:0] is received, the first data read from the SPI_DATA
register is a 16-bit data. The high 8 bits of this 16-bit data are zeros and the lower 8 bits are
D [23:16]. The second data read from the SPI_DATA register is D [15:0].
Figure 21-29. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=0)
I2S_CK
I2S_SD
16-bit 0
frame 1 (channel left)
frame 2 (channel right)
I2S_WS
16-bit data
MSB
LSB
Figure 21-30. LSB justified standard timing diagram (DTLEN=00, CHLEN=1, CKPL=1)
I2S_CK
I2S_SD
16-bit 0
frame 1 (channel left)
frame 2 (channel right)
I2S_WS
16-bit data
MSB
LSB
When the packet type is 16-bit data packed in 32-bit frame, only one write or read operation
to or from the SPI_DATA register is needed to complete a frame. The 16 remaining bits are
forced by hardware to 0x0000 to extend the data to 32-bit format.
PCM standard
For PCM standard, I2S_WS and I2S_SD are updated on the rising edge of I2S_CK, and the
I2S_WS signal indicates frame synchronization information. Both the short frame
synchronization mode and the long frame synchronization mode are available and
configurable using the PCMSMOD bit in the SPI_I2SCTL register. The SPI_DATA register is
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...