改文件是HOT-51电路原理图，该开发板功能很齐全，原理图可以为很多单片机硬件设计者提供参考。-Change the file is HOT-51 circuit diagram of the development board features a very complete schematic for many microcontroller hardware designers can provide a reference.

protel库文件，hot-51增强型开发板电路，原始电路图，绝无修改-protel library files, hot-51 enhanced development board circuit, the original circuit diagrams, no change