Synchronous Serial Port
LH79524/LH79525 User’s Guide
14-12
Version 1.0
14.2.2.2 Control Register 1 (CTRL1)
CTRL1 is the Control Register 1. CTRL1 contains four bit fields that control various SSP
functions.
Table 14-5. CTRL1 Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
SOD
MS
SSE
LBM
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
RW
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RW
RW
RW
RW
ADDR
0xFF 0x004
Table 14-6. CTRL1 Fields
BITS NAME
DESCRIPTION
31:4
///
Reserved
Reading returns 0. Write the reset value.
3
SOD
Slave Mode Output Disable
This bit is relevant only in the slave mode
(MS = 1). In multiple-slave systems, it is possible for an SSP master to broadcast a
message to all slaves in the system while ensuring that only one slave drives data
onto its serial output line. In such systems the RX lines from multiple slaves could
be tied together. To operate in such systems, the SOD bit can be programmed to 1.
1 = SSP must not drive the SSPTX output in slave mode
0 = SSP can drive the SSPTX output in slave mode
2
MS
Master or Slave Mode Select
This bit can only be modified when the SSP is
disabled, SSE = 0.
1 = device configured as slave
0 = device configured as master
1
SSE
Synchronous Serial Port Enable
This bit enables and disables the SSP.
1 = SSP operation is enabled
0 = SSP operation is disabled
0
LBM
Loopback Mode
Program this bit to enable or disable Loopback mode:
1 = Enables Loopback mode, internally connecting the Transmit serial shifter out-
put to the Receive serial shifter input
0 = Enables normal serial port operation, disabling Loopback mode