基于51单片机的Rs475通讯的程序及原理图仿真文件，用c语言来实现的。-a soft ware for Rs485 communication in 51MCU and the corresponding protel.

很全面的51控制超声波测距资料，包括protel 99se绘图文件。含多型号模块资料-Very comprehensive 51 control ultrasonic ranging, including protel 99se drawing file. Modules containing multi-model data