51 单片机 实现 计算器功能，通过键盘输入并且由数码管显示，由蜂鸣器判别按键音-51 MCU calculator function, through keyboard input and the digital display, touch-tone discrimination by the buzzer

基于51单片机的温度检测设计，DS18B20温度传感器，8位数码管显示-Design of temperature measurement based on 51 single chip microcomputer