CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
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(2) Asynchronous serial interface mode
This mode enables full-duplex operation, in which one byte of data is transmitted and received after the start bit.
The on-chip dedicated UARTn baud rate generator enables communications using a wide range of selectable
baud rates.
The UARTn baud rate generator can also be used to generate a MIDI-standard baud rate (31.25 Kbps).
(a) Register settings
The asynchronous serial interface mode settings are made via ASIMn, BRGCn, BRGMCn0, and BRGMCn1
(n = 0, 1).
Figure 10-38. ASIMn Setting (Asynchronous Serial Interface Mode)
After reset: 00H
R/W
Address: FFFFF300H, FFFFF310H
7
6
5
4
3
2
1
0
ASIMn
TXEn
RXEn
PS1n
PS0n
CLn
SLn
ISRMn
0
(n = 0, 1)
TXEn
RXEn
Operation mode
RXDn/Pxx pin function
TXDn/Pxx pin function
0
1
UARTn mode (receive only)
Serial function
Port function
1
0
UARTn mode (transmit only)
Port function
Serial function
1
1
UARTn mode (transmit and receive)
Serial function
Serial function
PS1n
PS0n
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
CLn
Character length specification
0
7 bits
1
8 bits
SLn
Stop bit length specification for transmit data
0
1 bit
1
2 bits
ISRMn
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
Caution Do not switch the operation mode until after the current serial transmit/receive operation has
stopped.