Introduction - If you have any usage issues, please Google them yourself
This report describes the AT89S52 microcontroller based on the core to AD0809 DAC chip sampling to the LCD screen display 1602 voltage measurement function with a certain precision digital voltmeter. On the basis of functional requirements in the realization of extension of the serial communication, clock function, high-pressure alarm, short-circuit test, resistance measurement, AC voltage peak and the cycle of testing and other functions, allowing the system to achieve a good design effects and requirements.