适用于8051的开发板。有串口，八段数码管，蜂鸣器，按键和扩展插针。使用protel 99绘制的电路图。原理图和PCB图完整。-8051 apply to the development board. Has serial port, eight digital tube, buzzer, buttons and expansion pin. Protel 99 using the circuit diagram drawn. Schematic and PCB Figure integrity