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GD32F20x User Manual
89
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
23:20
Reserved
Must be kept at reset value.
19
CKMEN
HXTAL Clock Monitor Enable
0: Disable the High speed 3 ~ 25 MHz crystal oscillator (HXTAL) clock monitor
1: Enable the High speed 3 ~ 25 MHz crystal oscillator (HXTAL) clock monitor
When the hardware detects that the HXTAL clock is stuck at a low or high state,
the internal hardware will switch the system clock to be the internal high speed
IRC8M RC clock. The way to recover the original system clock is by either an
external reset, power on reset or clearing CKMIF by software.
Note:
When the HXTAL clock monitor is enabled, the hardware will automatically
enable the IRC8M internal RC oscillator regardless of the control bit, IRC8MEN,
state.
18
HXTALBPS
High speed crystal oscillator (HXTAL) clock bypass mode enable
The HXTALBPS bit can be written only if the HXTALEN is 0.
0: Disable the HXTAL Bypass mode
1: Enable the HXTAL Bypass mode in which the HXTAL output clock is equal to
the input
clock.
17
HXTALSTB
High speed crystal oscillator (HXTAL) clock stabilization flag
Set by hardware to indicate if the HXTAL oscillator is stable and ready for use.
0: HXTAL oscillator is not stable
1: HXTAL oscillator is stable
16
HXTALEN
High Speed crystal oscillator (HXTAL) Enable
Set and reset by software. This bit cannot be reset if the HXTAL clock is used as
the system clock or the PLL input clock when PLL clock is selected to the system
clock. Reset by hardware when entering Deep-sleep or Standby mode.
0: High speed 3 ~ 25 MHz crystal oscillator disabled
1: High speed 3 ~ 25 MHz crystal oscillator enabled
15:8
IRC8MCALIB[7:0]
Internal 8MHz RC Oscillator calibration value register
These bits are load automatically when power on.
7:3
IRC8MADJ[4:0]
Internal 8MHz RC Oscillator clock trim adjust value
These bits are set by software. The trimming value is these bits (IRC8MADJ) added
to the IRC8MCALIB[7:0] bits. The trimming value should trim the IRC8M to 8 MHz
± 1%.
Содержание GD32F20 Series
Страница 1: ...GigaDevice Semiconductor Inc GD32F20x ARM Cortex M3 32 bit MCU User Manual Revision 2 2 Oct 2019 ...
Страница 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Страница 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Страница 385: ...GD32F20x User Manual 385 ...
Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...