电压检测和复位
RS804
The RS804 can monitor system voltages from 1.2V to 5.5V. When VCC voltage drops below the reset threshold, the device will send a reset signal. When VCC voltage rises to the reset threshold, the reset output remains low within a user-adjustable reset timeout period set by an external capacitor. The RS804 also features an excellent transient immunity to ignore fast VCC transients.
