#include <AT89X52.H>
#include <stdio.h>
#include <absacc.h>
unsigned char code table[] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f,};
unsigned char sec;        //定义计数值，每过1秒，sec加1
unsigned int tcnt;        //定时中断次数
bit  write = 0;           //写24C08的标志；
sbit gewei = P2 ^ 0;      //个位选通定义
sbit shiwei = P2 ^ 1;     //十位选通定义
/////////24C08读写驱动程序////////////////////
sbit scl = P3 ^ 4; // 24c08 SCL
sbit sda = P3 ^ 5; // 24c08 SDA

void delay1(unsigned char x)
{
    unsigned int i;
    for (i = 0; i < x; i++);
}

void flash()
{
    ;
}

void x24c08_init()  //24c08初始化子程序
{
    scl = 1;
    flash();
    sda = 1;
    flash();
}

void start()        //启动I2C总线
{
    sda = 1;
    flash();
    scl = 1;
    flash();
    sda = 0;
    flash();
    scl = 0;
    flash();
}

void stop()         //停止I2C总线
{
    sda = 0;
    flash();
    scl = 1;
    flash();
    sda = 1;
    flash();
}

void writex(unsigned char j)  //写一个字节
{
    unsigned char i, temp;
    temp = j;
    for (i = 0; i < 8; i++) {
        temp = temp << 1;
        scl = 0;
        flash();
        sda = CY;
        flash();
        scl = 1;
        flash();
    }
    scl = 0;
    flash();
    sda = 1;
    flash();
}

unsigned char readx()   //读一个字节
{
    unsigned char i, j, k = 0;
    scl = 0;
    flash();
    sda = 1;
    for (i = 0; i < 8; i++) {
        flash();
        scl = 1;
        flash();
        if (sda == 1) {
            j = 1;
        }
        else {
            j = 0;
        }
        k = (k << 1) | j;
        scl = 0;
    }
    flash();
    return (k);
}

void clock()         // I2C总线时钟
{
    unsigned char i = 0;
    scl = 1;
    flash();
    while ((sda == 1) && (i < 255)) {
        i++;
    }
    scl = 0;
    flash();
}

////////从24c02的地址address中读取一个字节数据/////
unsigned char x24c08_read(unsigned char address)
{
    unsigned char i;
    start();
    writex(0xa0);
    clock();
    writex(address);
    clock();
    start();
    writex(0xa1);
    clock();
    i = readx();
    stop();
    delay1(10);
    return (i);
}
//////向24c02的address地址中写入一字节数据info/////
void x24c08_write(unsigned char address, unsigned char info)
{
    EA = 0;
    start();
    writex(0xa0);
    clock();
    writex(address);
    clock();
    writex(info);
    clock();
    stop();
    EA = 1;
    delay1(50);
}

/////////////24C08读写驱动程序完/////////////////////
void Delay(unsigned int tc)     //延时程序
{
    while (tc != 0) {
        unsigned int i;
        for (i = 0; i < 100; i++);
        tc--;
    }
}

void LED()                  //LED显示函数
{
    shiwei = 0;
    P0 = table[sec / 10];
    Delay(8);
    shiwei = 1;
    gewei = 0;
    P0 = table[sec % 10];
    Delay(5);
    gewei = 1;
}

void t0(void) interrupt 1 using 0  //定时中断服务函数
{
    TH0 = (65536 - 50000) / 256; //对TH0 TL0赋值
    TL0 = (65536 - 50000) % 256; //重装计数初值
    tcnt++;        //每过250ust tcnt加一
    if (tcnt == 20) { //计满20次（1秒）时
        tcnt = 0; //重新再计
        sec++;
        write = 1; //1秒写一次24C08
        if (sec == 100) { //定时100秒，在从零开始计时
            sec = 0;
        }
    }
}

void main(void)
{
    TMOD = 0x01; //定时器工作在方式1
    ET0 = 1;
    EA = 1;
    x24c08_init();        //初始化24C08
    sec = x24c08_read(2); //读出保存的数据赋于sec
    TH0 = (65536 - 50000) / 256; //对TH0 TL0赋值
    TL0 = (65536 - 50000) % 256; //使定时器0.05秒中断一次
    TR0 = 1;         //开始计时
    while (1) {
        LED();
        if (write == 1) { //判断计时器是否计时一秒
            write = 0;            //清零
            x24c08_write(2, sec); //在24c08的地址2中写入数据sec
        }
    }
}