Serial Peripheral Interface Controller
UG0331 User Guide Revision 15.0
532
14.4.3.8 SPI Slave Select Register
The following table describes the register that specifies the slave that has been selected.
[7:0]
CLK_GEN
R/W 0
Specifies the methodology used to calculate the SPICLK divider.
CLK_MODE = 0:
SPICLK = 1 / (2
C 1
) where CLK_GEN = 0 to 15.
CLK_MODE = 1:
SPICLK = 1 / (2 × (C 1)) where CLK_GEN = 0 to 255.
Table 507 •
CLK_MODE Example, APB Clock = 153.8 MHz
CLK_MODE=0
CLK_MODE=1
SPICLK = 1 / (2
C 1
)
where CLKRATE = 0 to 15
SPICLK = 1 / (2 × (C 1))
where CLKRATE = 0 to 255
CLKRATE
SPI Clock
CLKRATE
SPI Clock
0
76,900,000
0
76,900,000
1
38,450,000
1
38,450,000
2
19,225,000
2
25,633,333.33
3
9,612,500
3
19,225,000
4
4,806,250
4
15,380,000
5
2,403,125
5
12,816,666.67
6
1,201,562.5
6
10,985,714.29
7
600,781.25
7
9,612,500
8
300,390.625
8
8,544,444.444
9
150,195.312
9
7,690,000
10
75,097.656
10
6,990,909.091
11
37,548.828
11
6,408,333.333
12
18,774.414
12
5,915,384.615
13
9,387.207
13
5,492,857.143
14
4,693.603
14
5,126,666.667
15
2,346.801
15
4,806,250
…
…
255
300,390.625
Table 508 •
SLAVE_SELECT
Bit
Number
Name
R/W
Reset
Value
Description
[31:8]
Reserved
R/W 0
Software should not rely on the value of a reserved bit. To provide
compatibility with future products, the value of a reserved bit should
be preserved across a read-modify-write operation.
Table 506 •
CLK_GEN
(continued)