c51单片机实验程序代码--流水灯、时钟、液晶驱动，串口异步通信、AD、DA、ROM 扩展、IO扩展等等，附原理图，对初学者很有帮助。-C51 single-chip experimental procedure code- water lights, clock, LCD driver, serial asynchronous communication, AD, DA, ROM expansion, IO expansion and so on, with schematic diagram