NEC mPD780852 Series Preliminary User's Manual page 176

(a) Asynchronous serial interface mode register (ASIM)
ASIM is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears ASIM to 00H.
Caution In UART mode, set the port mode register (PM5X) as follows. Besides that, set all output
latches to 0.
• When receiving
Set P53 (RxD) to the input mode (PM53 = 1)
• When transmitting
Set P54 (TxD) to the output mode (PM54 = 0)
• When transceiving
Set P53 to the input mode and P54 to the output mode
Address: FF85H After Reset: 00H
Symbol 7
ASIM TXE
TXE
0
0
1
1
PS1
0
0
1
1
CL
0
1
SL
0
1
ISRM
0
1
Cautions 1. Do not switch the operation mode until after the current serial transmit/receive
operation has stopped.
2. Bit 0 must be set to 0.
176
CHAPTER 13 SERIAL INTERFACE UART
R/W
6 5
RXE PS1 PS0
RXE Operation Mode
0 Operation stop
1 UART mode
(receive only)
0 UART mode
(transmit only)
1 UART mode
(transmit and receive)
PS0
0 No parity
1 Zero parity always added during transmission
No parity detection during reception (parity errors do not occur)
0 Odd parity
1 Even parity
Character Length Specification
7 bits
8 bits
Stop Bit Length Specification for Transmit Data
1 bit
2 bits
Receive Completion Interrupt Control When Error Occurs
Receive completion interrupt is issued when an error occurs
Receive completion interrupt is not issued when an error occurs
Preliminary User's Manual U14581EJ3V0UM00
4 3 2
CL SL
RxD/P53 Pin Function
Port function (P53)
Serial function (RxD)
Port function (P53)
Serial function (RxD)
Parity Bit Specification
1 0
ISRM 0
TxD/P54 Pin Function
Port function (P54)
Port function (P54)
Serial function (TxD)
Serial function (TxD)