24c02串行储存器.txt

24c02串行储存器

/*****************************************
******************************************
******************************************/
#include <reg51.h>
#include <intrins.h>
 
sbit SCL = P3^4;
sbit SDA = P3^5;

#define uchar unsigned char
#define uint  unsigned int

#define OP_WRITE 0xa0           // 器件地址以及写入操作
#define OP_READ  0xa1			// 器件地址以及读取操作

uchar code display[10]={0xff,0x15,0xe5,0xed,0x79,0xba,0x34,0xfe,0x46,0xeb};

/*******************函数声明**************************/
void start();
void stop();
uchar shin();
bit  shout(uchar write_data);
void write_byte( uchar addr, uchar write_data);
void fill_byte(uchar fill_size,uchar fill_data);
void delayms(uint ms);
uchar read_current();
uchar read_random(uchar random_addr);

/**********************************************************/
void delayms(uint ms) 
// 延时子程序
{
   	uchar k;
   	while(ms--)
   	{
    	for(k = 0; k < 120; k++);
   	}
}

/**********************************************************/
void start()
 //开始位
{
   	SDA = 1;
   	SCL = 1;
   	SDA = 0;
   	SCL = 0;
}

/**********************************************************/
void stop()
 // 停止位
{
   	SDA = 0;
   	SCL = 1;
   	SDA = 1;
}

/**********************************************************/
void fill_byte(uchar fill_size,uchar fill_data)
// 填充数据fill_data到EEPROM内fill_size字节
{
   	uchar i;
   	for(i = 0; i < fill_size; i++)
   	{
		write_byte(i, fill_data);
   	}
}

/**********************************************************/
uchar shin()
// 从AT24C02移出数据到MCU
{
   	uchar i,read_data;
   	for(i = 0; i < 8; i++)
   	{
   	 	SCL = 1;
    	read_data <<= 1;
    	read_data |= SDA;
    	SCL = 0;
   	}
    return(read_data);
}

/**********************************************************/
bit shout(uchar write_data) 
// 从MCU移出数据到AT24C02
{
   	uchar i;
   	bit ack_bit;
   	for(i = 0; i < 8; i++)   // 循环移入8个位
   	{
     	SDA = (bit)(write_data & 0x80);
    	SCL = 1;
    	SCL = 0;
    	write_data <<= 1;
   	}
   	SDA = 1;                     // 读取应答
   	SCL = 1;
   	ack_bit = SDA;
   	SCL = 0;
   	return (ack_bit);            // 返回AT24C02应答位
}

/**********************************************************/
void write_byte(uchar addr, uchar write_data)
// 在指定地址addr处写入数据write_data
{
   	start();
   	shout(OP_WRITE);
   	shout(addr);
   	shout(write_data);
   	stop();
   	delayms(10);          // 写入周期
}

/**********************************************************/
uchar read_current()
// 在当前地址读取
{
   	uchar read_data;
   	start();
   	shout(OP_READ);
   	read_data = shin();
   	stop();
   	return (read_data);
}

/**********************************************************/
uchar read_random(uchar random_addr)
// 在指定地址读取
{
   	start();
   	shout(OP_WRITE);
   	shout(random_addr);
   	return(read_current());
}

/**********************************************************/
void main(void)
{
	uchar i,j;
  	SDA = 1;
   	SCL = 1;
   	fill_byte(10,0xff);          // 将前10字节填充0xff
	
   	for(i = 0 ; i < 10; i++)    //写入显示代码到AT24C02
    	{
      		write_byte(i,display[i]);
    	}
   	for(i =0 ;i <10 ; i++)      //从AT24C02移出数据送到P0口显示
   	{
      		j=(read_random(i));
     		delayms(3500);
   	}
    	while(1);
}