CHAPTER 12 SERIAL INTERFACE 20
Table 12-2. Serial Interface 20 Operating Mode Settings
(1) Operation stop mode
ASIM20
CSIM20
PM25 P25 PM24 P24 PM23 P23
First
Bit
Shift
P25/SI20/
P24/SO20/ P23/SCK20/
TxD20 Pin ASCK20 Pin
Clock RxD20 Pin
Function
TXE20 RXE20 CSIE20 DIR20
CSCK20
Function
Function
Note 1
×
Note 1
×
Note 1
×
Note 1
×
Note 1
×
Note 1
×
0
0
0
×
×
−
−
P25
P24
P23
Other than above
Setting prohibited
(2) 3-wire serial I/O mode
ASIM20
CSIM20
PM25 P25 PM24 P24 PM23 P23
First
Bit
Shift
P25/SI20/
P24/SO20/ P23/SCK20/
TxD20 Pin ASCK20 Pin
Clock RxD20 Pin
Function
TXE20 RXE20 CSIE20 DIR20
CSCK20
0
Function
Function
Note 2
×
Note 2
×
0
0
1
1
0
1
0
1
1
0
1
0
×
1
×
1
MSB
SI20Note 2
External
SO20
(CMOS output)
SCK20
input
clock
1
0
1
SCK20
output
Internal
clock
LSB
SCK20
input
External
clock
SCK20
output
Internal
clock
Other than above
Setting prohibited
(3) Asynchronous serial interface mode
ASIM20
CSIM20
PM25 P25 PM24 P24 PM23 P23
First
Bit
Shift
P25/SI20/
P24/SO20/ P23/SCK20/
TxD20 Pin ASCK20 Pin
Clock RxD20 Pin
Function
TXE20 RXE20 CSIE20 DIR20
CSCK20
0
Function
Function
Note 1
×
Note 1
×
1
0
1
0
1
1
0
0
0
0
0
0
0
1
1
×
LSB
P22
TxD20
(CMOS output)
ASCK20
input
External
clock
Note 1
×
×
×
P23
Internal
clock
Note 1
Note 1
0
0
1
1
×
×
×
×
1
RxD20
P24
ASCK20
input
External
clock
Note 1
P23
Internal
clock
0
1
1
TxD20
ASCK20
input
External
clock
(CMOS output)
Note 1
P23
Internal
clock
Other than above
Setting prohibited
Notes 1. These pins can be used for port functions.
2. When only transmission is used, this pin can be used as P25 (CMOS I/O).
Remark ×: don’t care.
User’s Manual U15075EJ1V0UM00
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