GD32A50x User Manual
120
5.3.
Register definition
RCU base address: 0x4002 1000
5.3.1.
Control register (RCU_CTL)
Address offset: 0x00
Reset value: 0x0000 XX83 where X is undefined.
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
Reserved
PLLSTB
PLLEN
Reserved
HXTALSC
AL
LCKMEN PLLMEN CKMEN
HXTALB
PS
HXTALST
B
HXTALE
N
r
rw
rw
rw
rw
rw
rw
r
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
IRC8MCALIB[7:0]
IRC8MADJ[4:0]
Reserved
IRC8MST
B
IRC8MEN
r
rw
r
rw
Bits
Fields
Descriptions
31:26
Reserved
Must be kept at reset value.
25
PLLSTB
PLL clock stabilization flag
Set by hardware to indicate if the PLL output clock is stable and ready for use.
0: PLL is not stable
1: PLL is stable
24
PLLEN
PLL enable
Set and reset by software. This bit cannot be reset if the PLL clock is used as the
system clock. Reset by hardware when entering Deep-sleep or Standby mode.
0: PLL is switched off
1: PLL is switched on
23
Reserved
Must be kept at reset value.
22
HXTALSCAL
HXTAL frequency scale select
The HXTALSCAL bit can be written only if the HXTALEN is 0.
0: HXTAL scale is 2 ~ 8MHz
1: HXTAL scale is 8 ~ 40MHz
21
LCKMEN
LXTAL clock monitor enable
0: Disable the external 32.768k LXTAL clock monitor
1: Enable the external 32.768k LXTAL clock monitor
This bit cannot be set to 1, if the LXTAL clock or IRC40K clock is disabled.
LCKMEN enable the hardware detects that the LXTAL clock is stuck at a low/high