CHAPTER 16 ASYNCHRONOUS SERIAL INTERFACE/3-WIRE SERIAL I/O
User’s Manual U12697EJ3V0UM
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(a) Asynchronous serial interface mode registers 1 and 2 (ASIM1, ASIM2)
ASIM1 and ASIM2 can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ASIM1 and ASIM2 to 00H.
Address: 0FF70H, 0FF71H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
ASIMn
TXEn
RXEn
PSn1
PSn0
CLn
SLn
ISRMn
0
Note
TXEn
RXEn
Operation mode
RxD1/P20, RxD2/P70
TxD1/P21, TxD2/P71
pin function
pin function
0
0
Operation stop
Port function
Port function
0
1
UART mode
Serial function
Port function
(Receive only)
1
0
UART mode
Port function
Serial function
(Transmit only)
1
1
UART mode
Serial function
Serial function
(Transmit/Receive)
PSn1
PSn0
Parity bit specification
0
0
No parity
0
1
Always add 0 parity during transmission
Do not perform parity check during reception (parity error not generated)
1
0
Odd parity
1
1
Even parity
CLn
Character length specification
0
7 bits
1
8 bits
SLn
Transmit data stop bit length specification
0
1 bit
1
2 bits
ISRMn
Receive completion interrupt control at error occurrence
0
Generate receive completion interrupt when error occurs
1
Do not generate receive completion interrupt when error occurs
Note
Be sure to write “0” to bit 0.
Caution
Switch across to the operational mode after stopping serial sending and receiving
operations.
Remark
n = 1, 2