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I2C总线及AT24C02读写实验报告

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/**************************************************

实验名称：I2C总线实验一

实验目的：利用定时器产生0~99秒表在数码管前两位显示



每过一秒写入到AT24C02里面，关闭实验板后



重新打开实验板，秒表从AT24C02读入数据继



续上一次的计时。

实验备注：

**************************************************/

#include<reg52.h>

#define uchar unsigned char

#define uint unsigned int

sbit SDA = P2^0;

sbit SCL = P2^1;

sbit DUAN = P2^6;

sbit WEI = P2^7;

uchar code duan_table[]=

{0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

uchar code wei_table[]=

{0xfe,0xfd,0xfb,

0xf7,0xef,0xdf};

uchar num, sec;

void delay_1us();

void delay_1ms(uchar);

void display(uchar);

void at24_init();

void at24_start();

void at24_stop();

void at24_respons();

void at24_writebyte(uchar);

uchar at24_readbyte(uchar);

void at24_writeadd(uchar,uchar);

uchar at24_readadd(uchar);

void main()

{



at24_init();



sec = at24_readadd(5);



if(sec > 100)



sec = 0;



TMOD = 0x01;



TH0 = (65536-46080)/256;



TL0 = (65536-46080)%256;



EA = 1;



ET0 = 1;



TR0 = 1;



while(1)



{



if(num == 20)



{



num = 0;



sec++;



if(sec == 100)



{



sec = 0;



}



at24_writeadd(5,sec);



}



display(sec);



}

}

void delay_1us()

{

//


uchar i, j;

//


for(i = 0; i < 1; i++)

//


for(j = 0; j < 1; j++);

;;

}

void delay_1ms(uchar x)

{



uchar i, j;



for(i = 0; i < x; i++)



for(j = 0; j < 110; j++);

}

void display(uchar x)

{



DUAN = 1;



P0 = duan_table[x/10];



DUAN = 0;



P0 = 0xff;



WEI = 1;



P0 = wei_table[0];



WEI = 0;



delay_1ms(5);



DUAN = 1;



P0 = duan_table[x%10];



DUAN = 0;



P0 = 0xff;



WEI = 1;



P0 = wei_table[1];



WEI = 0;



delay_1ms(5);

}

void at24_init()

{



SDA = 1;



delay_1us();



SCL = 1;



delay_1us();

}

void at24_start()

{



SDA = 1;



delay_1us();



SCL = 1;



delay_1us();



SDA = 0;



delay_1us();

}

void at24_stop()

{



SDA = 0;      //必须先把SDA拉低



delay_1us();



SCL = 1;



delay_1us();



SDA = 1;



delay_1us();

}

void at24_respons()

{



uchar i;

//


i = 0;



SCL = 1;



delay_1us();



while((SDA == 1) && (i<250))



i++;



SCL = 0;



delay_1us();

}

void at24_writebyte(uchar dat)

{



uchar i,temp;



i = 0;



temp = dat;



for(i = 0; i < 8; i++)



{



temp = temp<<1;



SCL = 0;



delay_1us();



SDA = CY;



delay_1us();



SCL = 1;



delay_1us();



}



SCL = 0;



delay_1us();



SDA = 1;



delay_1us();

}

uchar at24_readbyte()

{



uchar i, temp;

//


i = 0;

//


temp = 0;



SCL = 0;



delay_1us();



SDA = 1;



delay_1us();



for(i = 0; i < 8; i++)



{



SCL = 1;



delay_1us();



temp = ((temp<<1) | SDA);



SCL = 0;



delay_1us();



}



return temp;

}

void at24_writeadd(uchar address,uchar dat)

{



EA = 0;



at24_start();



at24_writebyte(0xa0);



at24_respons();



at24_writebyte(address);



at24_respons();



at24_writebyte(dat);



at24_respons();



at24_stop();



EA = 1;



delay_1ms(5);

}

uchar at24_readadd(uchar address)

{



uchar temp;



at24_start();



at24_writebyte(0xa0);



at24_respons();



at24_writebyte(address);



at24_respons();



at24_start();



at24_writebyte(0xa1);



at24_respons();



temp = at24_readbyte();



at24_stop();



delay_1ms(1);



return temp;

}

void Timer0() interrupt 1

{



TH0 = (65536-46080)/256;



TL0 = (65536-46080)%256;



num++;

}

/**************************************************

实验名称：I2C总线实验二

实验目的：从键盘上读取两位数值，并储存在AT24C02里，



再从AT24C02中读取出来显示在数码管前两位。



1,数码管显示00的时候，按下键盘输入要储存



的两位数字。



2.数码管显示已经储存的数字，并等待键盘的



第二次输入。

实验备注：

**************************************************/

#include<reg52.h>

#define uchar unsigned char

#define uint unsigned int

sbit SDA = P2^0;

sbit SCL = P2^1;

sbit DUAN = P2^6;

sbit WEI = P2^7;

uchar code duan_table[]=

{0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

uchar code wei_table[]=

{0xfe,0xfd,0xfb,

0xf7,0xef,0xdf};

uchar code heng_table[]=

{0xfe, 0xfd, 0xfb, 0xf7, 0xef, 0xdf};

uchar num_led, num_i2c, flag_key, ge, shi;

void delay_4us();

void delay_1ms(uchar);

void display(uchar);

uchar keyscan();

uchar keynum();

void i2c_init();

void i2c_respons();

void i2c_start();

void i2c_stop();

void i2c_writebyte(uchar);

uchar i2c_readbyte();

void i2c_writeadd(uchar,uchar);

uchar i2c_readadd(uchar);

void main()

{



flag_key = 0;



num_led = 0;



num_i2c = 0;



i2c_init();



i2c_writeadd(3, num_i2c);



while(1)



{



display(num_led);



num_i2c = keynum();



if(flag_key == 3)



{



i2c_writeadd(3, num_i2c);



flag_key = 0;



}



num_led = i2c_readadd(3);



}

}

void delay_4us()

{;;}

void delay_1ms(uchar x)

{



uchar i, j;



for(i = 0; i < x; i++)



for(j = 0; j < 110; j++);

}

void display(uchar num)

{



DUAN = 1;



P0 = duan_table[num/10];



DUAN = 0;



P0 = 0xff;



WEI = 1;



P0 = wei_table[0];



WEI = 0;



delay_1ms(2);



DUAN = 1;



P0 = duan_table[num%10];



DUAN = 0;



P0 = 0xff;



WEI = 1;



P0 = wei_table[1];



WEI = 0;



delay_1ms(2);

}

uchar keyscan()

{



uchar key, temp;



key = 44;




P3 = heng_table[0];



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



delay_1ms(5);



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



temp = P3;



switch (temp)



{



case 0xee:



key = 1;



break;



case 0xde:



key = 2;



break;



case 0xbe:



key = 3;



break;



case 0x7e:



key = 4;



break;



}



while(temp != 0xf0)



{



temp = P3;



temp = temp & 0xf0;



}



}



}



P3 = heng_table[1];



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



delay_1ms(5);



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



temp = P3;



switch (temp)



{



case 0xed:



key = 5;



break;



case 0xdd:



key = 6;



break;



case 0xbd:



key = 7;



break;



case 0x7d:



key = 8;



break;



}



while(temp != 0xf0)



{



temp = P3;



temp = temp & 0xf0;



}



}



}



P3 = heng_table[2];



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



delay_1ms(5);



temp = P3;



temp = temp & 0xf0;



if(temp != 0xf0)



{



temp = P3;



switch (temp)



{



case 0xeb:



key = 9;



break;



case 0xdb:



key = 0;



break;



case 0xbb:



key = 11;



break;



case 0x7b:



key = 12;



break;



}



while(temp != 0xf0)



{



temp = P3;



temp = temp & 0xf0;



}



}




}



return key;

}

uchar keynum()

{



uchar temp;



temp = 0;



if(flag_key == 0)



{



shi = keyscan();



if(shi != 44)



{



flag_key = 1;



}



}



if(flag_key == 1)



{



ge = keyscan();



if(ge != 44)



{



flag_key = 2;



}



}



if(flag_key == 2)



{



temp = shi*10 + ge;



flag_key = 3;



}



return temp;

}

void i2c_init()

{



SCL = 1;



delay_4us();



SDA = 1;



delay_4us();

}

void i2c_respons()

{



uchar i;



i = 0;



SCL = 1;



delay_4us();



while((SDA ==1) && (i < 250))i++;



SCL = 0;



delay_4us();

}

void i2c_start()

{



SDA = 1;



delay_4us();



SCL = 1;



delay_4us();



SDA = 0;



delay_4us();

}

void i2c_stop()

{



SDA = 0;



delay_4us();



SCL = 1;



delay_4us();



SDA = 1;



delay_4us();

}

void i2c_writebyte(uchar x)

{



uchar i, temp;



temp = x;



for(i = 0; i < 8; i++)



{



temp = temp << 1;



SCL = 0;



delay_4us();



SDA = CY;



delay_4us();



SCL = 1;



delay_4us();



}



SCL = 0;



delay_4us();



SCL = 1;



delay_4us();

}

uchar i2c_readbyte()

{



uchar i ,temp;



SCL = 0;



delay_4us();



SDA = 1;



delay_4us();



for(i = 0; i < 8; i++)



{



SCL = 1;



delay_4us();



temp = ((temp << 1) | SDA);



SCL = 0;



}



return temp;

}

void i2c_writeadd(uchar address, uchar dat)

{



i2c_start();



i2c_writebyte(0xa0);



i2c_respons();



i2c_writebyte(address);



i2c_respons();



i2c_writebyte(dat);



i2c_respons();



i2c_stop();

}

uchar i2c_readadd(uchar address)

{



uchar temp;



i2c_start();



i2c_writebyte(0xa0);



i2c_respons();



i2c_writebyte(address);



i2c_respons();



i2c_start();



i2c_writebyte(0xa1);



i2c_respons();



temp = i2c_readbyte();



i2c_stop();



return temp;

}

转载于:https://blog.51cto.com/elvinsys/1611127


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