Electronics America Single-Chip Microcontrollers User's Manual

CHAPTER 11 SERIAL INTERFACE 20
212 User’s Manual U15331EJ4V1UD
(b) Asynchronous serial interface mode register 20 (ASIM20)
ASIM20 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ASIM20 to 00H.
When 3-wire serial I/O mode is selected, ASIM20 must be set to 00H.
TXE20
0
1
Transmit operation control
Transmit operation stopped
Transmit operation enabled
Receive operation stopped
Receive operation enabled
RXE20
0
1
0
1
0
0
0
1
0
1
1
1
No parity
Always add 0 parity at transmission.
Parity check is not performed at reception (no parity error occurs).
Odd parity
Even parity
Receive operation control
PS201
Parity bit specification
PS200
CL20
0
1
SL20
Transmit data character length specification
7 bits
8 bits
1 bit
2 bits
Transmit data stop bit length specification
TXE20 RXE20 PS201 PS200 CL20 SL20 0 0ASIM20
<7> <6> 5 4Symbol Address After reset R/W
FF70H 00H R/W
3210
Cautions 1. Bits 0 and 1 must be set to 0.
2. Switch operation modes after halting the serial transmission/reception operation.