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Rev. 1.00
480 of 576
January 28, 2022
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F54231/HT32F54241/HT32F54243/HT32F54253
22 Universal Synchronous
Asynchronous Receiver T
ransmitter (USART)
Register Descriptions
USART Data Register – USRDR
The register is used to access the USART transmitted and received FIFO data.
Offset:
0x000
Reset value: 0x0000_0000
31
30
29
28
27
26
25
24
Reserved
Type/Reset
23
22
21
20
19
18
17
16
Reserved
Type/Reset
15
14
13
12
11
10
9
8
Reserved
DB
Type/Reset
RW 0
7
6
5
4
3
2
1
0
DB
Type/Reset RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0 RW 0
Bits
Field
Descriptions
[8:0]
DB
Reading data from this receiver buffer register will return the data from the receive
FIFO. The receive FIFO has a capacity of up to 8 × 9 bits. By reading this register,
the USART will return a 7, 8 and 9-bit received data. The DB field bit 8 is valid for the
9-bit mode only and is fixed at 0 for the 8-bit mode. For the 7-bit mode, the DB[6:0]
field contains the available bits.
Writing data to this buffer register will load data into the Transmit FIFO. The Transmit
FIFO has a capacity of up to 8 × 9 bits. By writing to this register, the USART will
send out 7, 8 or 9-bit transmitted data. The DB field bit 8 is valid for the 9-bit mode
only and will be ignored for the 8-bit mode. For the 7-bit mode, the DB[6:0] field
contains the available bits.