用74HC164实现数码管的静态显示

要实现静态显示所用的IO较多，因此利用移位寄存器74HC164对IO的扩展来驱动数码管，从而实现静态显示。

硬件电路百度上很多，这里就不说了，写个程序吧

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int
const uchar table[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
                        0x07,0x7f,0x6f,0x77,0x7c,0x39,0x5e,0x79,0x71};
const uchar table1[]={0xbf,0x86,0xdb,0xcf,0xe6,0xed,0xfd,
                        0x87,0xff,0xef};
sbit dat=P2^0;
sbit clk=P2^1;
void disp(long a);
void write_bit(uchar num);
void main(void)
{
    disp(45678);
    while(1);   
}
void disp(long a)
{
    uchar ge,shi,bai,qian,wan;
    wan=a/10000;
    qian=a000/1000;
    bai=a00/100;
    shi=a0/10;
    ge=a;
    write_bit(table[wan]);
    write_bit(table[qian]);
    write_bit(table[bai]);
    write_bit(table[shi]);
    write_bit(table[ge]);
}
void write_bit(uchar num)
{
    uchar i;
    for(i=0;i<8;i++)
    {
        clk=0;                //时钟拉低，等待数据
        dat=(num&0x80)?1:0;   //最高位开始送，表达式为真时，结果为1，否则为0
        clk=1;                //时钟拉高，上升沿到来，164数据移位
        num<<=1;             
    }
}