GD32A50x User Manual
145
00: CK_CAN0 select CK_HXTAL
01: CK_CAN0 select CK_PCLK2
10: CK_CAN0 select CK_PCLK2/2
11: CK_CAN0 select CK_IRC8M
11:7
Reserved
Must be kept at reset value
7:6
USART2SEL[1:0]
CK_USART2 clock source selection
This bit is set and reset by software.
00: CK_USART2 select CK_HXTAL
01: CK_USART2 select CK_SYS
10: CK_USART2 select CK_LXTAL
11: CK_USART2 select CK_IRC8M
5:4
USART1SEL[1:0]
CK_USART1 clock source selection
This bit is set and reset by software.
00: CK_USART1 select CK_HXTAL
01: CK_USART1 select CK_SYS
10: CK_USART1 select CK_LXTAL
11: CK_USART1 select CK_IRC8M
3:2
Reserved
Must be kept at reset value
1:0
USART0SEL[1:0]
CK_USART0 clock source selection
This bit is set and reset by software.
00: CK_USART0 select CK_HXTAL
01: CK_USART0 select CK_SYS
10: CK_USART0 select CK_LXTAL
11: CK_USART0 select CK_IRC8M
5.3.14.
Voltage key register (RCU_VKEY)
Address offset: 0x100
Reset value: 0x0000 0000.
This register can be accessed by byte(8-bit), half-word(16-bit) and word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
KEY[31:16]
w
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
KEY[15:0]
w
Bits
Fields
Descriptions
31:0
KEY[31:0]
The key of RCU_DSV register
These bits are written only by software and read as 0. Only after write