CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U12688EJ4V0UM00
291
(2) Asynchronous serial interface status registers 0, 1 (ASIS0, ASIS1)
These registers are configured with 3-bit error flags (PEn, FEn, OVEn), which show the error status when
UARTn reception is terminated, and a transmit status flag (SOTn) (n = 0,1).
The status flag that shows a receive error always shows the state of the error that occurred most recently.
That is, if the same error occurred several times before reading of receive data, this flag would hold the status
of the error that occurred most recently.
If a receive error occurs, after reading the ASISn register, read the receive buffer (RXBn or RXBnL) and clear
the error flag.
These are read-only registers in 8- or 1-bit units.
Address
FFFFF0C4H
7
SOT0
ASIS0
6
0
5
0
4
0
3
0
2
PE0
1
FE0
0
OVE0
After reset
00H
FFFFF0D4H
SOT1
ASIS1
0
0
0
0
PE1
FE1
OVE1
00H
Bit Position
Bit Name
Function
7
SOTn
Status Of Transmission
This is a status flag that shows the transmission operation’s state.
Set (1):
Transmission start timing (writing to the TXSn or TXSnL register)
Clear (0): Transmission end timing (generation of the INTSTn interrupt)
When about to start serial data transmission, use this as a means of judging whether
writing to the transmit shift register is enabled or not.
2
PEn
Parity Error
This is a status flag that shows a parity error.
Set (1):
When transmit parity and receive parity do not match.
Clear (0): Data are read from the receive buffer and processed.
1
FEn
Framing Error
This is a status flag that shows a framing error.
Set (1):
When a stop bit was not detected.
Clear (0): Data are read from the receive buffer and processed.
0
OVEn
Overrun Error
This is a status flag that shows an overrun error.
Set (1):
When UARTn has finished the next receiving processing before fetching
receive data from the receive buffer.
Clear (0): Data are read from the receive buffer and processed.
Furthermore, due to the configuration where 1 frame at a tie is received, then the
contents of the receive shift register are transmitted to the receive buffer, when an
overrun error has occurred, the next receive data is written over the data existing in the
receive buffer, and the previous receive data is discarded.
Remark
n = 0, 1
Содержание V850E/MS1 UPD703100
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