GD32F20x User Manual
65
register with an expected wakeup time and enable the wakeup function so that it can achieve
the RTC timer wakeup event. After entering the power saving mode for a certain amount of
time, the RTC will wake up the device when the time match event occurs. The details of the
RTC configuration and operation will be described in the
When the Backup domain is supplied by V
DD
(V
BAK
pin is connected to V
DD
), the following
functions are available:
PC13 can be used as GPIO or RTC function pin described in the RTC chapter.
PC14 and PC15 can be used as either GPIO or LXTAL Crystal oscillator pins.
PI8 can be used as GPIO or RTC function pin described in the RTC chapter
When the Backup domain is supplied by V
BAT
(V
BAK
pin is connected to V
BAT
), the following
functions are available:
PC13 can be used as RTC function pin described in the RTC chapter.
PC14 and PC15 can be used as LXTAL Crystal oscillator pins only.
PI8 can be used as RTC function pin described in the RTC chapter.
Note:
Since PC13, PC14, PC15 are supplied through the Power Switch, which can only be
obtained by a small current, the speed of GPIOs PC13 to PC15 should not exceed 2MHz
when they are in output mode(maximum load: 30pF)
3.3.2.
V
DD
/V
DDA
power domain
V
DD
/V
DDA
domain includes two parts: V
DD
domain and V
DDA
domain. V
DD
domain includes
HXTAL (High Speed Crystal oscillator), LDO (Voltage Regulator), POR/PDR (Power
On/Down Reset), FWDGT (Free Watchdog Timer), all pads except PC13/PC14/PC15, etc.
V
DDA
domain includes ADC/DAC (AD/DA Converter), IRC8M (Internal 8MHz RC oscillator),
IRC48M (Internal 48MHz RC oscillator at 48MHz frequency), IRC40K (Internal 40KHz RC
oscillator), PLLs (Phase Locking Loop), LVD (Low Voltage Detector), etc.
V
DD
domain
The LDO, which is implemented to supply power for the 1.2V domain, is always enabled after
reset. It can be configured to operate in three different status, including in the Sleep mode
(full power on), in the Deep-sleep mode (on or low power), and in the Standby mode (power
off).
The POR/PDR circuit is implemented to detect V
DD
/V
DDA
and generate the power reset signal
which resets the whole chip except the Backup domain when the supply voltage is lower than
the specified threshold.
Figure 3-2. Waveform of the POR/PDR
between the supply voltage and the power reset signal. V
POR
, which typical value is 2.40V,
indicates the threshold of power on reset, while V
PDR
, which typical value is 1.80V, means the
threshold of power down reset. The hysteresis voltage (V
hyst
) is around 600mV.
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 ...
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Страница 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
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Страница 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...