数码管的动态显示

数码管动态显示的实质就是利用了人眼视觉的暂留和二极管的余晖作用

由于人的视觉暂留现象及发光二极管的余辉效应，尽管实际上各位数码管并非同时点亮，但只要扫描的速度足够快，给人的印象就是一组稳定的显示数据，不会有闪烁感，动态显示的效果和静态显示是一样的，能够节省大量的I/O端口，而且功耗更低。

目标-

第一个数码管显示1 时间500ms 熄灭第二个显示2 时间500ms到第六个显示6 一直循环下去

写法一：

#include<reg52.h>
#define uint unsigned int 
#define uchar unsigned char
sbit du = P2^6;
sbit we = P2^7;
unsigned code leddata[]={ 
 
                0x3F,  //"0"
                0x06,  //"1"
                0x5B,  //"2"
                0x4F,  //"3"
                0x66,  //"4"
                0x6D,  //"5"
                0x7D,  //"6"
                0x07,  //"7"
                0x7F,  //"8"
                0x6F,  //"9"
                0x77,  //"A"
                0x7C,  //"B"
                0x39,  //"C"
                0x5E,  //"D"
                0x79,  //"E"
                0x71,  //"F"
                0x76,  //"H"
                0x38,  //"L"
                0x37,  //"n"
                0x3E,  //"u"
                0x73,  //"P"
                0x5C,  //"o"
                0x40,  //"-"
                0x00,  //熄灭
                0x00  //自定义
 
                         };


void delay(uint xms)
{
    uint x, y;
    for(x=xms;x>0;x--)
        for(y=114;y>0;y--);
}                         

void main()
{
    while(1)
 {
    du = 1;
    P0 = leddata[1];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xfe;
    we = 0;
    delay(500);
    
    du = 1;
    P0 = leddata[2];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xfd;
    we = 0;
    delay(500);
    
    du = 1;
    P0 = leddata[3];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xfb;
    we = 0;
    delay(500);
    
    du = 1;
    P0 = leddata[4];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xf7;
    we = 0;
    delay(500);
    
    du = 1;
    P0 = leddata[5];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xef;
    we = 0;
    delay(500);
    
    du = 1;
    P0 = leddata[6];
    du = 0;
    P0 = 0xff;
    we = 1;
    P0 = 0xdf;
    we = 0;
    delay(500);
    
 }    
}

这是我以前的写法，现在觉得好蠢。。。

写法二：

#include<reg52.h>
#include<intrins.h>
sbit du = P2^6;
sbit we = P2^7;
#define uint unsigned int
#define uchar unsigned char
uchar i;
uchar temp;
unsigned code leddata[]={ 

0x3F, //"0"
0x06, //"1"
0x5B, //"2"
0x4F, //"3"
0x66, //"4"
0x6D, //"5"
0x7D, //"6"
0x07, //"7"
0x7F, //"8"
0x6F, //"9"
0x77, //"A"
0x7C, //"B"
0x39, //"C"
0x5E, //"D"
0x79, //"E"
0x71, //"F"
0x76, //"H"
0x38, //"L"
0x37, //"n"
0x3E, //"u"
0x73, //"P"
0x5C, //"o"
0x40, //"-"
0x00, //熄灭
0x00 //自定义

};
void delay(uint xms)
{
    uint x, y;
    for(x=xms; x>0; x--)
        for(y=114;y>0;y--);
}

int main()
{
    while(1)
    {
        we = 1;
        P0 = 0xfe;
        we = 0;
        temp = P0;
        for(i=1;i<=6;i++)
        {
            du = 1;
            P0 = leddata[i];
            du = 0;
            P0 = 0xff;

            we = 1;
            P0 = temp;
            temp = crol_(temp,1);
            we = 0;
            delay(500);
        }
    }

    return 0;
}

写法二就简单了很多，用for解决了重复的代码

思考：为什么段选完之后要P0=oxff
就是为了不影响位选
这条语句的专业名称叫做消影