SN8P1700
8-bit micro-controller build-in 12-bit ADC
In worse-power condition as brown out reset. The reset pin may keep high level but the VDD is low voltage. That
makes the system reset fail and chip error. To connect a diode from reset pin to VDD is a good solution. The circuit
can force the capacitor to release electric charge and drop the voltage, and solve the error.
R
VDD
DIODE
20K ohm
RST
MCU
C
0.1uF
VSS
VCC
GND
Figure 6-4. External Reset Circuit with Diode
LOW VOLTAGE DETECTOR (LVD) DESCRIPTION
The LVD is a low voltage detector. It detects VDD level and reset the system as the VDD lower than the desired
voltage. The detect level is 2.4V. If the VDD lower than 2.4V, the system resets. The LVD function is controlled by code
option. Users can turn on it for special application like worse power condition. LVD work with external reset function.
They are OR active.
VDD
LVD Detect Level
LVD
System Reset
End of LVD Reset
Figure 6-5. LVD Timing Diagram
The LVD can protect system to work well under brownout reset. But it is a high consumptive circuit. In 3V condition, the
LVD consumes about 100uA. It is a very large consumption for battery system. So the LVD supports AC system well.
ꢂ
Notice: LVD is selected by code option.
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