Holtek HT32F50231 User Manual page 473

32-Bit Arm ® Cortex ® -M0+ MCU
HT32F50231/HT32F50241
Bits Field
[7] TXDE
[5] RXDR
[4] BII
[3] FEI
[2] PEI
[1] OEI
Rev. 1.00
Descriptions
Transmit Data Register Empty
0: Transmit data register is not empty
1: Transmit data register is empty
The TXDE bit is set by hardware when the content of the transmit data register is
transferred to the transmit shift register (TSR). An interrupt is generated if TXEIE = 1
in the URIER register. This bit is cleared by a write to the URDR register with a new
data.
RX Data Ready
0: Receive data register is empty
1: Received data in the receive data register is ready to read
This bit is set by hardware when the content of the receive shift register RDR has
been transferred to the URDR register. An interrupt is generated if RXDRIE = 1 in
the URIER register. It is cleared by a read to the URDR register.
Break Interrupt Indicator
This bit is set to 1 whenever the received data input is held in the "spacing state"
(logic 0) for longer than a full character transmission time, which is the total time of
"start bit" + "data bits" + "parity" + "stop bits" duration. Writing 1 to this bit clears the
flag.
Framing Error Indicator
This bit is set 1 whenever the received character does not have a valid "stop bit",
which means the stop bit following the last data bit or parity bit is detected as logic 0.
Writing 1 to this bit clears the flag.
Parity Error Indicator
This bit is set to 1 whenever the received character does not have a valid "parity bit".
Writing 1 to this bit clears the flag.
Overrun Error Indicator
An overrun error will occur only after the receive data register is full and when
the next character has been completely received in the receive shift register. The
character in the receive shift register will be overwritten when a new character is
received in the receive shift register after an overrun event occurs, but the data in
the receive shift register will not be transferred to the receive data register. The OEI
bit is used to indicate the overrun event as soon as it happens. Writing 1 to this bit
clears the flag.
473 of 486 July 31, 2018