linux I2C读写EEPROM

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

//文件名：app_at24c02.c

//功能:测试linux下iic读写at24c02程序

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

//包含头文件

#include

#include

#include

#include

#include

#include

#include

#include

#include

#include

//宏定义

#define Address 0x50                  //at24c02地址

#define I2C_RETRIES   0x0701

#define I2C_TIMEOUT   0x0702

#define I2C_SLAVE     0x0703       //IIC从器件的地址设置

#define I2C_BUS_MODE   0x0780

typedef unsigned char uint8;

uint8 rbuf[8] = {0x00}; //读出缓存

uint8 wbuf[8] = {0x01,0x05,0x06,0x04,0x01,0x01,0x03,0x0d}; //写入缓存

int fd = -1;

//函数声明

static uint8 AT24C02_Init(void);

static uint8 i2c_write(int fd, uint8 reg, uint8 val);

static uint8 i2c_read(int fd, uint8 reg, uint8 *val);

static uint8 printarray(uint8 Array[], uint8 Num);

//at24c02初始化

static uint8 AT24C02_Init(void)

{

  fd = open("/dev/i2c/0", O_RDWR);   //允许读写

  if(fd < 0)

    {

        perror("Can't open /dev/nrf24l01 \n"); //打开iic设备文件失败

        exit(1);

    }

    printf("open /dev/i2c/0 success !\n");   //打开iic设备文件成功

  if(ioctl(fd, I2C_SLAVE, Address)<0) {    //设置iic从器件地址

                printf("fail to set i2c device slave address!\n");

                close(fd);

                return -1;

        }

  printf("set slave address to 0x%x success!\n", Address);

    if(ioctl(fd, I2C_BUS_MODE, 1)<0)     //设置iic总线模式

            printf("set bus mode fail!\n");

    else

            printf("set bus mode ok!\n");

    return(1);

}

/*

uint8 AT24C02_Write(uint8 *nData, uint8 Reg, uint8 Num)

{

  write(fd, &Reg, 1);  //

  usleep(100);              //延时100us

  write(fd, nData, Num);

  usleep(1000*4);             //延时 4ms

  return(1);

}

uint8 AT24C02_Read(uint8 nData[], uint8 Reg, uint8 Num)

{

  write(fd, &Reg, 1); 

  usleep(100);              //延时100us

  read(fd, nData, Num);

  usleep(1000*4);             //延时 4ms

  return(1);

}

*/

//at24c02写入一字节

static uint8 i2c_write(int fd, uint8 reg, uint8 val)

{

        int retries;

        uint8 data[2];

        data[0] = reg;

        data[1] = val;

        for(retries=5; retries; retries--) {

                if(write(fd, data, 2)==2)

                        return 0;

                usleep(1000*10);

        }

        return -1;

}

//at24c02读取一字节

static uint8 i2c_read(int fd, uint8 reg, uint8 *val)

{

        int retries;

        for(retries=5; retries; retries--)

                if(write(fd, ®, 1)==1)

                        if(read(fd, val, 1)==1)

                                return 0;

        return -1;

}

//输出数组

static uint8 printarray(uint8 Array[], uint8 Num)

{

  uint8 i;

  for(i=0;i

  {

    printf("Data [%d] is %d \n", i ,Array[i]);

  }

  return(1);

}

//主函数

int main(int argc, char *argv[])

{

  int i;

  AT24C02_Init();

  usleep(1000*100);

    for(i=0; i

            if(i2c_read(fd, i, &rbuf[i]))

                    break;

  printarray(rbuf ,8);

  printf("Before Write Data \n");

  sleep(1);

    for(i=0; i

            if(i2c_write(fd, i, wbuf[i]))

                    break;

  printarray(wbuf ,8);

  printf("Writing Data \n");

  sleep(1);

    for(i=0; i

            if(i2c_read(fd, i, &rbuf[i]))

                    break;

  printarray(rbuf ,8);

  printf("After Write Data \n");

  close(fd);

}