51单片机，用ADC0809做成的数字电压表，效果不错的，有仿真。-51, made with the ADC0809 digital voltage meter, good results, there are simulation.

数字万用表功能板卡驱动封装，需配合NI数字万用表模拟或真实板卡使用实现万用表测量功能-Digital multimeter function interface card driver package, need to cooperate with NI digital multimeter implementation multimeter is used to measure the function simulation or real interface card

DMM4020数字万用表的驱动代码，可以用来驱动DMM4020万用表进行测试-the driver code of digital multimeter DMM4020,you can use this to ctrl the DMM4020 multimeter.