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Rev. 1.00
79 of 486
July 31, 2018
32-Bit Arm
®
Cortex
®
-M0+ MCU
HT32F50231/HT32F50241
6 Clock Control Unit (CKCU)
Global Clock Control Register – GCCR
This register specifies the clock enable bits.
Offset:
0x004
Reset value: 0x0000_0803
31
30
29
28
27
26
25
24
Reserved
Type/Reset
23
22
21
20
19
18
17
16
Reserved
PSRCEN
CKMEN
Type/Reset
RW 0 RW 0
15
14
13
12
11
10
9
8
Reserved
HSIEN
HSEEN
Reserved HSEGAIN
Type/Reset
RW 1 RW 0
RW 0
7
6
5
4
3
2
1
0
Reserved
SW
Type/Reset
RW 0 RW 1 RW 1
Bits
Field
Descriptions
[17]
PSRCEN
Power Saving Wakeup RC Clock Enable
0: No action
1: Use Internal RC clock (HSI) as system clock after a Deep-Sleep1/2 mode wakeup
Software can set PSRCEN to high before entering Deep-Sleep1/2 mode in order to
reduce the waiting time after wakeup. When PSRCEN = 1, hardware will select HSI
as clock source after the system wakeup from Deep-Sleep1/2 mode. Meanwhile,
instruction can start execution since the HSI clock is provided to MCU. After the
original clock source, which is selected as CK_SYS before entering Deep-Sleep1/2
mode, is ready, hardware will switch back the clock source as originally.
[16]
CKMEN
HSE Clock Monitor Enable
0: Disable External crystal oscillator clock monitor
1: Enable External crystal oscillator clock monitor
When hardware detects HSE clock stuck at low / high state, internal hardware will switch
the system clock to internal high speed RC clock (HSI). The only way to recover the
system clock is by an external reset, a power on reset or by clearing CKSF by software.
[11]
HSIEN
Internal High Speed Clock Enable
0: Internal RC oscillator clock is set to off
1: Internal RC oscillator clock is set to on
Set and reset by software. This bit can not be reset if HSI clock is used as system clock.
[10]
HSEEN
External High Speed Clock Enable
0: External crystal oscillator clock is set to off
1: External crystal oscillator clock is set to on
Set and reset by software. This bit can not be reset if the HSE clock is used as
system clock.