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CHAPTER 14 SERIAL INTERFACE UART
(a) Asynchronous serial interface mode register (ASIM)
ASIM is set with a 1-bit or 8-bit memory manipulation instruction.
When RESET is input, its value is 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 (R
X
D) to the input mode (PM53 = 1)
• When transmitting
Set P54 (T
X
D) 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 R/W
Symbol
7
6
5
4
3
2
1
0
ASIM
TXE
RXE
PS1
PS0
CL
SL
ISRM
0
TXE
RXE
Operation Mode
RxD/P53 Pin Function
TxD/P54 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 and receive)
PS1
PS0
Parity Bit Specification
0
0
No parity
0
1
Zero parity always added during transmission
No parity detection during reception (parity errors do not occur)
1
0
Odd parity
1
1
Even parity
CL
Character Length Specification
0
7 bits
1
8 bits
SL
Stop Bit Length Specification for Transmit Data
0
1 bit
1
2 bits
ISRM
Receive Completion Interrupt Control when Error Occurs
0
Receive completion interrupt is issued when an error occurs
1
Receive completion interrupt is not issued when an error occurs
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.
Summary of Contents for mPD780973 Series
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