#include <reg52.h>
#include <intrins.h>

sbit we=P2^7;
sbit du=P2^6;

unsigned char code table[] = {
0x3f , 0x06 , 0x5b , 0x4f,
0x66 , 0x6d , 0x7d , 0x07,
0x7f , 0x6f , 0x77 , 0x7c,
0x39 , 0x5e , 0x79 , 0x71,
0x00};

void ini_t0();
void show();
void delayms(unsigned time);
void keyscan();
void matrixscan();


unsigned char num[6]={0,0,16,0,0,16};
unsigned char count=0;
unsigned char nums=0;

void main()
{
      ini_t0();
    
    while(1)
    {
        keyscan();
        num[1]=nums/10;
        num[0]=nums%10;
        matrixscan();
        show();
    }
}

void matrixscan()
{
    unsigned char i,j;
    unsigned char temp;

    for(i=0;i<4;i++)
    {
        P3=~(1<<i);        //第i+1行给低电平
        if((P3|0x0f)!=0xff)    //判断此时是否有列为低电平
        {                    //有则得到行列位置i+1,j+1
            delayms(10);
            if((temp=P3|0x0f)!=0xff)
            {
                while((P3|0x0f)!=0xff);
                for(j=0;j<4 && ( temp& 0x10<<j );j++)
                    ;
                num[4]=i+1;
                num[3]=j+1;
                break;
            }
        }
    }
    P3=0xff;    //还原电平
}

void keyscan()
{
    unsigned char temp;

    if((P3|0x0f)!=0xff)
    {
        delayms(10);
        if((temp=P3|0x0f)!=0xff)
        {
            while((P3|0x0f)!=0xff);
            switch(temp)
            {
            case 0xef:
                if(++nums==60)
                    nums=0;
                break;
            case 0xdf:
                if(nums--==0)
                    nums=59;
                break;
            case 0xbf:
                nums=0;
                break;
            case 0x7f:
                TR0=~TR0;
                break;
            }
        }
    }
}

void t0_time() interrupt 1
{
    TH0=(65536-45872)/256;
    TL0=(65536-45872)%256;
    count++;

    if(count==20)
    {
        count=0;
        if(++nums==60)
            nums=0;
    }
}

void ini_t0()
{
    EA=1;
    ET0=1;
    TMOD=0x01;
    TH0=(65536-45872)/256;
    TL0=(65536-45872)%256;
}

void show()
{
    unsigned char i;
    
    for(i=0;i<6;i++)
    {
        P0=0xff;
        we=1;
        we=0;      

        P0=table[num[i]];
        du=1;
        du=0;

        P0=~(0x20>>i);
        we=1;
        we=0;

        delayms(1);
    }
}

void delayms(unsigned time)
{
    unsigned i,j;

    for(i=time;i>0;i--)
        for(j=110;j>0;j--)
        ;
}