GD32F20x User Manual
109
5.3.9.
Backup domain control register (RCU_BDCTL)
Address offset: 0x20
Reset value: 0x0000 0018, reset by Backup domain Reset.
This register can be accessed by byte(8-bit),half-word(16-bit) and word(32-bit)
Note:
The LXTALEN, LXTALBPS, LXTALDRI, RTCSRC and RTCEN bits of the Backup
domain control register (RCU_BDCTL) are only reset after a Backup domain Reset. These
bits can be modified only when the BKPWEN bit in the Power control register (PMU_CTL)
has to be set.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
BKPRST
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
RTCEN
Reserved
RTCSRC[1:0]
Reserved
LXTALDRI[1:0]
LXTAL
BPS
LXTAL
STB
LXTALEN
rw
rw
rw
rw
r
rw
Bits
Fields
Descriptions
31:17
Reserved
Must be kept at reset value
16
BKPRST
Backup domain reset
This bit is set and reset by software.
0: No reset
1: Resets Backup domain
15
RTCEN
RTC clock enable
This bit is set and reset by software.
0: Disabled RTC clock
1: Enabled RTC clock
14:10
Reserved
Must be kept at reset value
9:8
RTCSRC[1:0]
RTC clock entry selection
Set and reset by software to control the RTC clock source. Once the RTC clock
source has been selected, it cannot be changed anymore unless the Backup
domain is reset.
00: No clock selected
01: CK_LXTAL selected as RTC source clock
10: CK_IRC40K selected as RTC source clock
11: (CK_HXTAL / 128) selected as RTC source clock
7:5
Reserved
Must be kept at reset value
4:3
LXTALDRI[1:0]
LXTAL drive capability
Set and reset by software. Backup domain reset resets this value.
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...