AT32F425
Series Reference Manual
2022.03.30
Page 178
Ver 2.01
Table 13-1 Audio frequency precision using system clock
SCLK
(MHz)
MCL
K
Target
Fs
(Hz)
16bit
32bit
I2S
DIV
I2S_ODD
RealFs
Error
I2S
DIV
I2S_ODD
RealFs
Error
72
No
192000
6
0
187500
2.34%
3
0
187500
2.34%
72
No
96000
11
1
97826.09
1.90%
6
0
93750
2.34%
72
No
44100
25
1
44117.65
0.04%
13
0
43269.23
1.88%
72
No
32000
35
0
32142.86
0.45%
17
1
32142.86
0.45%
72
No
22050
51
0
22058.82
0.04%
25
1
22058.82
0.04%
72
No
16000
70
1
15957.45
0.27%
35
0
16071.43
0.45%
72
No
11025
102
0
11029.41
0.04%
51
0
11029.41
0.04%
72
No
8000
140
1
8007.117
0.09%
70
1
7978.723
0.27%
72
Yes
48000
3
0
46875
2.34%
3
0
46875
2.34%
72
Yes
44100
3
0
46875
6.29%
3
0
46875
6.29%
72
Yes
32000
4
1
31250
2.34%
4
1
31250
2.34%
72
Yes
22050
6
1
21634.62
1.88%
6
1
21634.62
1.88%
72
Yes
16000
9
0
15625
2.34%
9
0
15625
2.34%
72
Yes
11025
13
0
10817.31
1.88%
13
0
10817.31
1.88%
72
Yes
8000
17
1
8035.714
0.45%
17
1
8035.714
0.45%
13.3.6 DMA transfer
The SPI supports write and read operations with DMA. Whether used as SPI or I
2
S, read/write request
using DMA comes from the same peripheral. As a result, their configuration procedure are the same,
described as follows.
Transmission with DMA
Select DMA channel: Select a DMA channel for the current SPI from DMA channel map table
described in DMA chapter.
Configure the destination of DMA transfer: Configure the SPI_DT register address as the
destination address bit of DMA transfer in the DMA control register. Datat will be sent to this address
after transmit request is received by DMA.
Configure the source of DMA transfer: Configure the memory address as the source of DMA
transfer in the DMA control register. Data will be loaded into the SPI_DT register from the memory
address after transmit request is received by DMA.
Configure the total number of bytes to be transferred in the DMA control register.
Configure the channel priority of DMA transfer in the DMA control register.
Configure DMA interrupt generation after half or full transfer in the DMA control register.
Enable DMA transfer channel in the DMA control register.
Reception with DMA
Select DMA transfer channel: Select a DMA channel for the current SPI from DMA channel map
table described in DMA chapter.
Configure the destination of DMA transfer: Configure the memory address as the destination of
DMA transfer in the DMA control register. Data will be loaded from the SPI_DT register to the
programmed destination after reception request is received by DMA.
Configure the source of DMA transfer: Configure the SPI_DT register address as the source of
DMA transfer in the DMA control register. Data will be loaded from the SPI_DT register to the
programmed destination after reception request is received by DMA.
Configure the total number of bytes to be transferred in the DMA control register.
Configure the total number of bytes to be transferred in the DMA control register.
Configure DMA interrupt generation after half or full transfer in the DMA control registe
Enable DMA transfer channel in the DMA control register.