Rev. 2.10
228
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Rev. 2.10
229
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HT68F20/HT68F30/HT68F40/HT68F50/HT68F60
HT68FU30/HT68FU40/HT68FU50/HT68FU60
Enhanced I/O Flash Type 8-Bit MCU with EEPROM
HT68F20/HT68F30/HT68F40/HT68F50/HT68F60
HT68FU30/HT68FU40/HT68FU50/HT68FU60
Enhanced I/O Flash Type 8-Bit MCU with EEPROM
Bit 4
OERR
: Overrun error flag
0: No overrun error is detected
1: Overrun error is detected
The OERR flag is the overrun error flag which indicates when the receiver buffer has
overflowed. When this read only flag is "0", it indicates that there is no overrun error.
When the flag is "1", it indicates that an overrun error occurs which will inhibit further
transfers to the RXR receive data register. The flag is cleared by a software sequence,
which is a read to the status register USR followed by an access to the RXR data
register.
Bit 3
RIDLE
: Receiver status
0: Data reception is in progress (data being received)
1: No data reception is in progress (receiver is idle)
The RIDLE flag is the receiver status flag. When this read only flag is "0", it indicates
that the receiver is between the initial detection of the start bit and the completion of
the stop bit. When the flag is "1", it indicates that the receiver is idle. Between the
completion of the stop bit and the detection of the next start bit, the RIDLE bit is "1"
indicating that the UART receiver is idle and the RX pin stays in logic high condition.
Bit 2
RXIF
: Receive RXR data register status
0: RXR data register is empty
1: RXR data register has available data
The RXIF flag is the receive data register status flag. When this read only flag is "0",
it indicates that the RXR read data register is empty. When the flag is 1, it indicates
that the RXR read data register contains new data. When the contents of the shift
register are transferred to the RXR register, an interrupt is generated if RIE=1 in the
UCR2 register. If one or more errors are detected in the received word, the appropriate
receive-related flags NF, FERR, and/or PERR are set within the same clock cycle. The
RXIF flag is cleared when the USR register is read with RXIF set, followed by a read
from the RXR register, and if the RXR register has no data available.
Bit 1
TIDLE
: Transmission idle
0: Data transmission is in progress (data being transmitted)
1: No data transmission is in progress (transmitter is idle)
The TIDLE flag is known as the transmission complete flag. When this read only flag
is 0, it indicates that a transmission is in progress. This flag will be set to "1" when the
TXIF flag is 1 and when there is no transmit data or break character being transmitted.
When TIDLE is equal to "1", the TX pin becomes idle with the pin state in logic high
condition. The TIDLE flag is cleared by reading the USR register with TIDLE set and
then writing to the TXR register. The flag is not generated when a data character or a
break is queued and ready to be sent.
Bit 0
TXIF
: Transmit TXR data register status
0: Character is not transferred to the transmit shift register
1: Character has transferred to the transmit shift register (TXR data register is empty)
The TXIF flag is the transmit data register empty flag. When this read only flag is "0",
it indicates that the character is not transferred to the transmitter shift register. When
the flag is "1", it indicates that the transmitter shift register has received a character
from the TXR data register. The TXIF flag is cleared by reading the UART status
register (USR) with TXIF set and then writing to the TXR data register. Note that
when the TXEN bit is set, the TXIF flag bit will also be set since the transmit data
register is not yet full.