GD32VF103 User Manual
49
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
..
PC14 and PC15 can be used as either GPIO or LXTAL Crystal oscillator pins.
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
..
PC14 and PC15 can be used as LXTAL Crystal oscillator pins only.
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), 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
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 2.35V, means the
threshold of power down reset. The hysteresis voltage (V
hyst
) is around 50mV.