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18 UART
0x4100: UART Status Register (UART_ST)
Register name Address
Bit
UART Status
0x4100
D7
Register
(8 bits)
D6
(UART_ST)
D5
D4
D3
D2
D1
D0
D7
Reserved
D6
FER: Framing Error Flag
Indicates whether a framing error has occurred.
1 (R):
Error occurred
0 (R):
No error (default)
1 (W):
Reset to 0
0 (W):
Disabled
FER is set to 1 when a framing error occurs. Framing errors occur when data is received with the stop
bit set to 0.
FER is reset by writing as 1 or by setting RXEN (D0/UART_CTL register) to 0.
D5
PER: Parity Error Flag
Indicates whether a parity error has occurred.
1 (R):
Error occurred
0 (R):
No error (default)
1 (W):
Reset to 0
0 (W):
Disabled
PER is set to 1 when a parity error occurs. Parity checking is enabled only when PREN (D3/
UART_MOD register) is set to 1 and is performed when received data is transferred from the shift reg-
ister to the receive data buffer.
PER is reset by writing as 1 or by setting RXEN (D0/UART_CTL register) to 0.
D4
OER: Overrun Error Flag
Indicates whether an overrun error has occurred.
1 (R):
Error occurred
0 (R):
No error (default)
1 (W):
Reset to 0
0 (W):
Disabled
OER is set to 1 when an overrun error occurs. Overrun errors occur when data is received in the shift
register when the receive data buffer is already full and additional data is sent. The receive data buffer
is not overwritten if this error occurs. The shift register is overwritten as soon as the error occurs.
OER is reset by writing as 1 or by setting RXEN (D0/UART_CTL register) to 0.
D3
RD2B: Second Byte Received Flag
Indicates that the receive data buffer contains two items of received data.
1 (R):
Second byte can be read
0 (R):
Second byte not received (default)
RD2B is set to 1 when the second byte of data is loaded into the receive data buffer and is reset to 0
when the first data is read from the receive data buffer.
224
Name
Function
–
reserved
FER
Framing error flag
PER
Parity error flag
OER
Overrun error flag
RD2B
Second byte receive flag
TRBS
Transmit busy flag
RDRY
Receive data ready flag
TDBE
Transmit data buffer empty flag
Setting
–
1 Error
0 Normal
1 Error
0 Normal
1 Error
0 Normal
1 Ready
0 Empty
1 Busy
0 Idle
1 Ready
0 Empty
1 Empty
0 Not empty
EPSON
Init. R/W
Remarks
–
–
0 when being read.
0
R/W Reset by writing 1.
0
R/W
0
R/W
0
R
0
R
Shift register status
0
R
1
R
S1C17001 TECHNICAL MANUAL
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