基于74HC164扩展单片机系统I/O端口的研究

Research of Extend MCU System I/O Ports Based on 74HC164

随着面向应用的增加,单片机系统I/O端口数量有限的问题日益突出。根据74HC164串行输入、并行输出的工作原理,对单片机系统的I/O端口进行扩展。设计具有16个按键的中断串行键盘和具有8个数码管的串行数码管显示,用4个I/O端口完成了传统并行技术中需要24个I/O端口才能实现的功能。给出了硬件电路、程序和需要注意的问题。实践表明,基于74HC164扩展单片机系统I/O端口的效果良好。

With the development of applications, Micro Controller Unit（MCU） system faces the problem of limited I/O Ports is serious increasingly. According to 74HC164 s principle of serial input and parallel output, extends MCU system I/O Ports. Designs an interrupt serial keyboard with 16 buttons and serial display with 8 numerical-code-tube, uses 4 I/O Ports to realize the function that needs 24 I/O Ports via traditional method. Supports the hardware circuit, programme and keys. The result shows that extends MCU system I/O Ports based on 74HC164 has good effect in practice.