CHAPTER 11 SERIAL INTERFACE FUNCTION
User’s Manual U14359EJ4V0UM
393
<7>
<6>
5
<4>
3
2
1
<0>
Address
After reset
CSIM0
CSICAE0 TRMD0
0
DIR0
0
0
0
CSOT0
FFFFF900H
00H
CSIM1
CSICAE1 TRMD1
0
DIR1
0
0
0
CSOT1
FFFFF910H
00H
CSIM2
CSICAE2 TRMD2
0
DIR2
0
0
0
CSOT2
FFFFF920H
00H
Bit position
Bit name
Function
7
CSICAEn
(n = 0 to 2)
CSI Operation Permission/Prohibition
Specifies whether CSIn operation is enabled or disabled (n = 0 to 2).
0: CSIn operation is disabled (SOn = low level, SCKn = high level)
1: CSIn operation is enabled
Cautions 1.
If CSICAEn is set to 0, the CSIn unit can be reset
asynchronously.
2.
If CSICAEn = 0, the CSIn unit is in a reset state. Therefore, to
operate CSIn, CSICAEn must be set to 1.
3.
If the CSICAEn bit is changed from 1 to 0, all registers of the
CSIn unit are initialized. To set CSICAEn to 1 again, the
registers of the CSIn unit must be set again.
6
TRMDn
(n = 0 to 2)
Transmission/Reception Mode Control
Specifies the transmission/reception mode.
0: Reception-only mode
1: Transmission/reception mode
If TRMDn = 0, reception-only transfers are performed. In addition, the SOn pin
output is fixed at low level. Data reception is started by reading the SIOn register.
If TRMDn = 1, transmission/reception is started by writing data to the SOTBn
register.
Caution The TRMDn bit can be overwritten only when CSOTn = 0.
4
DIRn
(n = 0 to 2)
Transmit Direction Mode Control
Specifies the transfer direction mode (MSB or LSB).
0: The transfer data’s start bit is MSB
1: The transfer data’s start bit is LSB
Caution The DIRn bit can be overwritten only when CSOTn = 0.
0
CSOTn
(n = 0 to 2)
CSI Status of Transmission
This is a transfer status display flag.
0: Idle status
1: Transfer execution status
This flag is used to judge whether writing to the shift register (SIOn) is enabled or
not when starting serial data transmission in transmission/reception mode
(TRMDn = 1)
Caution The CSOTn bit is reset when the CSICAEn bit is cleared (0).