linux下iic(i2c)读写AT24C02

/jammy_lee/

linux下iic（i2c）读写AT24C02

linux驱动2010-02-09 16:02:03 阅读955 评论3 字号：大中小订阅

linux内核上已有iic的驱动，因此只需要对该iic设备文件进行读写则能够控制外围的iic器件。这里以AT24C02为对象，编写一个简单的读写应用程序。iic设备文件在我的开发板上/dev/i2c/0 ，打开文件为可读写。AT24C02的器件地址为0x50 ，既是iic总线上从器件的地址，每次只读写一字节数据。

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

//文件名：app_at24c02.c

//功能:测试linux下iic读写at24c02程序

//使用说明: (1)

// (2)

// (3)

// (4)

//作者:jammy-lee

//日期:2010-02-08

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

//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;