移植并修改成功的模拟iic读写EEPROM at24c02

2010-04-24 12:58:00

注：如果要读24c128或264，地址位为16位的。现在的地址位为8位。

protues仿真图

源程序如下：

#include <iom16v.h>
#include <macros.h>
#include "delay.h"
#define I2C_DDR     DDRB
#define I2C_PORT    PORTB
#define I2C_PIN     PINB
#define SDA         PB1
#define SCL         PB0

#define SDA_OUT()   (I2C_DDR |= (1<<SDA))
#define SCL_OUT()   (I2C_DDR |= (1<<SCL))
// 释放SDA，上拉输入
#define SDA_RLS()   do{ I2C_PORT |= (1<<SDA); I2C_DDR &= ~(1<<SDA); }while(0)
#define SCL_RLS()   do{ I2C_PORT |= (1<<SCL); I2C_DDR &= ~(1<<SCL); }while(0)
#define SDA_SET()   (I2C_PORT |= (1<<SDA))
#define SDA_CLR()   (I2C_PORT &= ~(1<<SDA))
#define SCL_SET()   (I2C_PORT |= (1<<SCL))
#define SCL_CLR()   (I2C_PORT &= ~(1<<SCL))
#define READ_SDA() ((I2C_PIN & (1<<SDA)) ? 1 : 0)

#define i2c_delay() delay_us(1)       // 根据系统时钟进行调整
#define AT24C02_WRITE_ADDR 0xA0
#define AT24C02_READ_ADDR   0xA1
#define PAGE_SIZE   8
#define PAGE_MASK   (PAGE_SIZE-1)
// 发送起始信号
void i2c_start(void)
{
        SDA_SET();
  i2c_delay();
        SCL_SET();
        i2c_delay();
        SDA_CLR();
        i2c_delay();
        SCL_CLR();
  //i2c_delay();
}

// 发送停止信号
void i2c_stop(void)
{
    SDA_CLR();
    i2c_delay();
    SCL_SET();
    i2c_delay();
    SDA_SET();
   // i2c_delay();
}

// 向总线写1字节，并返回从机有无应答
unsigned char i2c_write(unsigned char byte)
{
    unsigned char i, ack;
    ack = 0;
    for( i = 0; i < 8; ++i ){
        if ( byte & 0x80)
            SDA_SET();
        else
                SDA_CLR();
        byte <<= 1;
        SCL_SET();
        i2c_delay();
        SCL_CLR();
    }

    SDA_RLS();
    i2c_delay();
    SCL_SET();
    i2c_delay();
    ack = READ_SDA();
    SCL_CLR();
    i2c_delay();
SDA_OUT();
    return ack;
}

// 读1字节，ack=1时，发送ACK，ack=0，发送nACK
unsigned char i2c_read(unsigned char ack)
{
unsigned char i, r = 0;

    SDA_RLS();
    for( i = 0; i < 8; i++ ){
        SCL_SET();
        i2c_delay();
        r <<= 1;
        if ( READ_SDA() == 1)
        {
            r |= 1;
        }
        SCL_CLR();
        i2c_delay();
    }

    SDA_OUT();
    // Send ACK
    if (!ack)
        SDA_SET();      // Send nACK
    else
        SDA_CLR();      // Send ACK
    i2c_delay();
    SCL_SET();
    i2c_delay();
    SCL_CLR();
    i2c_delay();
    return r;
}

void at24c02_write1byte(unsigned int byte_addr, unsigned char byte)
{
    i2c_start();
    i2c_write(AT24C02_WRITE_ADDR);
//i2c_write(byte_addr>>8);      //输入15-9高位
    i2c_write(byte_addr);
    i2c_write(byte);
    i2c_stop();
    delay_ms(20);      // 等待10ms，保证24C02内部写操作完成
}

void at24c02_page_write(unsigned char byte_addr, unsigned char *buff, unsigned char num)
{
    unsigned char i;
    i2c_start();
    i2c_write(AT24C02_WRITE_ADDR);
    i2c_write(byte_addr);
    for( i = 1; i <= num; ++i )
    {
        i2c_write(*buff);
        buff++;
    }
    i2c_stop();
    delay_ms(20);
}

void at24c02_writenbytes(unsigned char byte_addr, unsigned char *buff, unsigned char num)
{
    unsigned char n_tmp;
    n_tmp = PAGE_SIZE - (unsigned char)(byte_addr & PAGE_MASK); // 本页内剩余空间数量
    if ((num > n_tmp) && (n_tmp != 0))
    {
        // 先将本页剩余空间写满
        at24c02_page_write(byte_addr, buff, n_tmp);
        byte_addr += n_tmp;
        num -= n_tmp;
        buff += n_tmp;
    }
    while( num >= PAGE_SIZE ){
        at24c02_page_write(byte_addr, buff, PAGE_SIZE);
        byte_addr += PAGE_SIZE;
        num -= PAGE_SIZE;
        buff += PAGE_SIZE;
    }
    if (num != 0)
    {
        at24c02_page_write(byte_addr, buff, num);
    }
}

unsigned char at24c02_read_curr_addr(void)
{
    unsigned char data;
    i2c_start();
    i2c_write(AT24C02_READ_ADDR);
    data = i2c_read(0);     // 读1字节，返回nACK
    i2c_stop();
    return data;
}

unsigned char at24c02_read1byte(unsigned char byte_addr)
{
    unsigned char data;
    i2c_start();
    i2c_write(AT24C02_WRITE_ADDR);
//i2c_write(byte_addr>>8);       //输入15-9高位
    i2c_write(byte_addr);
    i2c_start();
    i2c_write(AT24C02_READ_ADDR);
    data = i2c_read(0);     // 读1字节，返回nACK
    i2c_stop();
    return data;

}

void at24c02_readnbytes(unsigned char byte_addr, unsigned char *buff, unsigned char num)
{
    unsigned char i;
    i2c_start();
    i2c_write(AT24C02_WRITE_ADDR);
    i2c_write(byte_addr);
    i2c_start();
    i2c_write(AT24C02_READ_ADDR);
    for( i = 1; i <= num-1; ++i )
    {
        *buff = i2c_read(1);        // 读1字节返回ack
        buff++;
    }
    *buff = i2c_read(0);
    i2c_stop();
}

void port_init(void)
{
PORTA=0xff;
DDRA=0xff;
SDA_OUT();
SCL_OUT();
}

void main(void)
{
    unsigned char temp1[8]={1,2,3,4,5,6,7,8};
    unsigned char temp2[8]={0};
port_init();
    at24c02_writenbytes(0x03,temp1,8);// write the byte 01h at address 03h
    at24c02_readnbytes(0x03,temp2,8);  // read the byte 01h at address 03h
     //SDA_RLS() ;
  //SCL_RLS() ;
    while (1)
    {
if(temp2[0]==1)
     {
      PORTA=0XFE;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

     if(temp2[1]==2)
     {
      PORTA=0XFD;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

      if(temp2[2]==3)
     {
      PORTA=0XFB;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

      if(temp2[3]==4)
     {
      PORTA=0XF7;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

      if(temp2[4]==5)
     {
      PORTA=0XEF;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

      if(temp2[5]==6)
     {
      PORTA=0XDF;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

       if(temp2[6]==7)
     {
      PORTA=0XBF;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }

      if(temp2[7]==8)
     {
      PORTA=0X7F;
      delay_ms(100);
      PORTA=0XFF;
   delay_ms(50);
     }
}
}

移植并修改成功的模拟iic读写EEPROM at24c02

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