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Rev. 1.00
483 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
22 Universal Synchronous
Asynchronous Receiver T
ransmitter (USART)
22 Universal Synchronous
Asynchronous Receiver T
ransmitter (USART)
USART FIFO Control Register – USRFCR
This register specifies the USART FIFO control and configurations including threshold level and reset function
together with the USART FIFO status.
Offset:
0x008
Reset value: 0x0000_0000
31
30
29
28
27
26
25
24
Reserved
RXFS
Type/Reset
RO 0 RO
0 RO 0 RO
0
23
22
21
20
19
18
17
16
Reserved
TXFS
Type/Reset
RO
0 RO
0 RO 0 RO
0
15
14
13
12
11
10
9
8
Reserved
Type/Reset
7
6
5
4
3
2
1
0
RXTL
TXTL
Reserved
RXR
TXR
Type/Reset RW 0 RW 0 RW 0 RW 0
WO 0 WO 0
Bits
Field
Descriptions
[27:24]
RXFS
RX FIFO Status
The RXFS field shows the current number of data contained in the RX FIFO.
0000: RX FIFO is empty
0001: RX FIFO contains 1 data
...
1000: RX FIFO contains 8 data
Others: Reserved
[19:16]
TXFS
TX FIFO Status
The TXFS field shows the current number of data contained in the TX FIFO.
0000: TX FIFO is empty
0001: TX FIFO contains 1 data
...
1000: TX FIFO contains 8 data
Others: Reserved
[7:6]
RXTL
RX FIFO Threshold Level Setting
00: 1 data
01: 2 data
10: 4 data
11: 6 data
The RXTL field defines the RX FIFO trigger level.
[5:4]
TXTL
TX FIFO Threshold Level Setting
00: 0 data
01: 2 data
10: 4 data
11: 6 data
The TXTL field determines the TX FIFO trigger level.
[1]
RXR
RX FIFO Reset
Setting this bit will generate a reset pulse to reset the RX FIFO which will empty the
RX FIFO, i.e., the RX pointer will be reset to 0 after a reset signal. This bit returns to
0 automatically after the reset pulse is generated.