CHAPTER 12 SERIAL INTERFACE 20
(c) Asynchronous serial interface status register 20 (ASIS20)
ASIS20 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets ASIS20 to 00H.
Symbol
ASIS20
7
0
6
0
5
0
4
0
3
0
<2>
<1>
<0>
Address
FF71H
After reset
00H
R/W
R
PE20
FE20
OVE20
PE20
Parity error flag
0
1
No parity error has occured
A parity error has occured (when the parity of transmit data does not match)
Framing error flag
FE20
0
1
No framing error has occured
A framing error has occured (when stop bit is not detected)Note 1
OVE20
Overrun error flag
No overrun error has occured
0
1
An overrun error has occuredNote 2
(when the next receive operation is completed before data is read from reception buffer register 20)
Notes 1. Even when the stop bit length is set to 2 bits by setting bit 2 (SL20) of asynchronous serial
interface mode register 20 (ASIM20), the stop bit detection at reception is performed with 1
bit.
2. Be sure to read reception buffer register 20 (RXB20) when an overrun error occurs. If not,
every time the data is received an overrun error will occur.
User’s Manual U15075EJ1V0UM00
227
NEC [ NEC ]
