LM3S1G21 Datasheet, PDF (764/955 Pages) Texas Instruments – Stellaris® LM3S1G21 Microcontroller

Synchronous Serial Interface (SSI)
Register 5: SSI Clock Prescale (SSICPSR), offset 0x010
The SSICPSR register specifies the division factor which is used to derive the SSIClk from the
system clock. The clock is further divided by a value from 1 to 256, which is 1 + SCR. SCR is
programmed in the SSICR0 register. The frequency of the SSIClk is defined by:
SSIClk = SysClk / (CPSDVSR * (1 + SCR))
The value programmed into this register must be an even number between 2 and 254. The
least-significant bit of the programmed number is hard-coded to zero. If an odd number is written
to this register, data read back from this register has the least-significant bit as zero.
SSI Clock Prescale (SSICPSR)
SSI0 base: 0x4000.8000
SSI1 base: 0x4000.9000
Offset 0x010
Type R/W, reset 0x0000.0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
reserved
Type RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
reserved
CPSDVSR
Type RO
RO
RO
RO
RO
RO
RO
RO
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit/Field
31:8
7:0
Name
reserved
CPSDVSR
Type
RO
R/W
Reset
0x00
0x00
Description
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.
SSI Clock Prescale Divisor
This value must be an even number from 2 to 254, depending on the
frequency of SSIClk. The LSB always returns 0 on reads.
764
January 22, 2012
Texas Instruments-Production Data