说明：  单片机原理及实验以及源程序 实验一 功能：使连接在 MCS-51 单片机 P1.0 引脚的 LED 闪烁。 实验二 设计并调试一个双字节无符号数乘法子程序 实验三：设计并调试一个将双字节无符号二进制数转换为压缩 BCD数的子程序。 实验四：利用外部中断输入引脚（中断方式）控制步进电机的转动。
(The principle and experiment of single chip microcomputer and the source program Experiment 1 function: make the LED flashing on the P1.0 pin of MCS-51 microcontroller flicker. Experiment two design and debug a double byte unsigned multiplication subroutine. Experiment three: design and debug a subroutine that converts the double byte unsigned binary number to the compressed BCD number. Experiment four: use external interrupt input pin (interrupt mode) to control the rotation of stepper motor.)