凌阳单片机的按键与显示程序，键盘接在IOB8~IOB15.液晶显示接在IOB8~IOB15。-Sunplus buttons and display program, the keyboard connected to the IOB8 ~ IOB15. Liquid crystal display connected to the IOB8 ~ IOB15.

用AT89C2051单片机的两路定时器实现两路6种频率的方波信号输出，根据按键选择改变频率-AT89C2051 microcontroller implemented using two two six kinds timer frequency square wave signal output, according to changes in the frequency button to select