Asynchronous Serial Interface Status Register Format - NEC PD78081(A) User Manual

(3) Asynchronous serial interface status register (ASIS)
This is a register which displays the type of error when a reception error is generated in the asynchronous
serial interface mode.
ASIS is read with a 1-bit or 8-bit memory manipulation instruction.
In 3-wire serial I/O mode, the contents of the ASIS are undefined.
RESET input sets ASIS to 00H.
Figure 11-5. Asynchronous Serial Interface Status Register Format
Symbol
7 6 5
ASIS 0 0 0
Notes 1. The receive buffer register (RXB) must be read when an overrun error is generated. Overrun errors
will continue to be generated until RXB is read.
2. Even if the stop bit length has been set as 2 bits by bit 2 (SL) of the asynchronous serial interface
mode register (ASIM), only single stop bit detection is performed during reception.
CHAPTER 11 SERIAL INTERFACE CHANNEL 2
4 3 2 1
0 0 PE FE
0 Address After Reset
OVE FF71H 00H
OVE Overrun Error Flag
0 Overrun error not generated
Overrun error generated
1 (When next receive operation is completed before
data from receive buffer register is read)
FE Framing Error Flag
0 Framing error not generated
Framing error generated
1
(When stop bit is not detected)
PE Parity Error Flag
0 Parity error not generated
Parity error generated (When transmit data parity
1
does not match)
R/W
R
Note 1
Note 2
143