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Chapter 15
Serial Interface Channel UART
User’s Manual U16504EE1V1UD00
15.5 Serial Interface Operations
This section explains the different modes of the UART.
15.5.1 Operation stop mode
This mode is used when serial transfer is performed to reduce power consumption.
In the operation stop mode, pins can be used as ordinary ports.
Register settings
Operation stop mode settings are made via the asynchronous serial interface mode register (ASIM0).
TXE0 and RXE0 must be set to 0.
Figure 15-5:
Register Settings
Caution:
Do not switch the operation mode until the current serial transmit/receive operation
has stopped.
<7>
<6>
5
4
3
2
1
0
R/W
Address
After
Reset
00H
ASIM0
TXE0
RXE0
PS01
PS00
CL0
SL0
ISRM0
0
R/W
FFA0H
TXE0
RXE0
Operation mode
RXD0/P62 pin function
TXD0/P63 pin function
0
0
Operation stop
Port function
Port function
0
1
UART0 mode
(receive only)
Serial operation
Port function
1
0
UART0 mode
(transmit only)
Port function
Serial operation
1
1
UART0 mode
(transmit and receive)
Serial operation
Serial operation