LM3S301 Luminary Micro, Inc, LM3S301 Datasheet - Page 274

• Manufacturer Part Number: LM3S301
• Description: Lm3s301 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

Synchronous Serial Interface (SSI)
274
Reset
Reset
Type
Type
SSI Control 0 (SSICR0)
Offset 0x000
31:16
R/W
RO
31
15
0
0
15:8
Bit
7
6
Register 1: SSI Control 0 (SSICR0), offset 0x000
SSICR0 is control register 0 and contains bit fields that control various functions within the SSI
module. Functionality such as protocol mode, clock rate and data size are configured in this
register.
R/W
RO
30
14
0
0
reserved
Name
SCR
SPO
SPH
R/W
RO
29
13
0
0
R/W
RO
28
12
0
0
SCR
Type
R/W
R/W
R/W
RO
R/W
RO
27
11
0
0
R/W
RO
26
10
0
0
Reset
0
0
0
0
R/W
RO
25
0
9
0
Preliminary
Description
Reserved bits return an indeterminate value, and should never
be changed.
SSI Serial Clock Rate
The value SCR is used to generate the transmit and receive bit
rate of the SSI. The bit rate is:
BR= F
where CPSDVR is an even value from 2-254 programmed in the
SSICPSR register, and SCR is a value from 0-255.
SSI Serial Clock Phase
This bit is only applicable to the Freescale SPI Format.
The SPH control bit selects the clock edge that captures data
and allows it to change state. It has the most impact on the first
bit transmitted by either allowing or not allowing a clock
transition before the first data capture edge.
When the SPH bit is 0, data is captured on the first clock edge
transition. If SPH is 1, data is captured on the second clock edge
transition.
SSI Serial Clock Polarity
This bit is only applicable to the Freescale SPI Format.
When the SPO bit is 0, it produces a steady state Low value on
the SSIClk pin. If SPO is 1, a steady state High value is placed
on the SSIClk pin when data is not being transferred.
R/W
RO
24
0
8
0
reserved
SSICLK
SPH
R/W
RO
23
0
7
0
/(CPSDVR * (1 + SCR))
SPO
R/W
RO
22
0
6
0
R/W
RO
21
0
5
0
FRF
R/W
RO
20
0
4
0
R/W
RO
19
0
3
0
R/W
RO
18
0
2
0
DSS
R/W
RO
17
July 5, 2006
0
1
0
R/W
RO
16
0
0
0