分享一个i2c 24c02驱动

发布于 2019-03-08 14:01:13 浏览：2129 订阅该版

* 本帖最后由 uskd 于 2019-3-8 14:06 编辑 *

#include <rtthread.h>
#include <rtdevice.h>
#define AT24C02_TEST_DATA 0xCC /* 测试数据 */

static const char *AT24C02_I2C_BUS_NAME ="i2c1"; /* I2c总线设备名称*/
/*****在ARM中，读写方向是用寄存器的单独一位来确定的，有一个7位的域用来保存设备地址。所以该I2C设备在ARM  I2C总线上的地址为0xA0  右移一位 0x50.**************/
static const rt_uint8_t AT24C02_ADDR = 0x50;    /* 从机地址 */
static struct rt_i2c_bus_device *i2c_bus = RT_NULL;     /* I2C总线设备句柄 */
static rt_bool_t initialized = RT_FALSE;                /* 初始化状态*/

/****************************************************************************
* 名    称: u8 AT24C02_ReadReg
* 功    能：在AT24C02读寄存器
* 入口参数：ReadAddr：要读取数据所在的地址
* 返回参数：读到的8位数据
* 说    明：  
****************************************************************************/
static rt_err_t AT24C02_ReadReg(struct rt_i2c_bus_device *bus,rt_uint8_t reg, rt_uint8_t len, rt_uint8_t *buf)
{                
   struct rt_i2c_msg msgs[2];
    rt_uint8_t buff[1];
    msgs[0].addr = AT24C02_ADDR;/*写地址*/
    msgs[0].flags = RT_I2C_WR;
    msgs[0].buf = ®                        /*寄存器*/
    msgs[0].len = 1;
        
    msgs[1].addr  = AT24C02_ADDR;/*地址*/
    msgs[1].flags = RT_I2C_RD;       /* 读取*/
    msgs[1].buf   = buff;             /* 缓冲区 */
    msgs[1].len   = len;             /* 长度 */

/* I2C传输数据 */
 if( rt_i2c_transfer(bus, msgs, 2) == 2 )
 { 
 *buf = buff[0];
 rt_kprintf("传输值：%02X ",buff[0]);
 return RT_EOK;
 }
 else
 {
 return -RT_ERROR;
 } 
}

/****************************************************************************
* 名    称: u8 AT24C02_WriteByte(u8 WriteAddr,u8 WriteData)
* 功    能：在AT24C02指定地址写入一个数据
* 入口参数

* 返回参数： 
* 说 明： 
****************************************************************************/
static rt_err_t AT24C02_WriteReg(struct rt_i2c_bus_device *bus, rt_uint8_t reg, rt_uint8_t *data)
{ 
 struct rt_i2c_msg msgs[2];
 rt_uint8_t *buf; 
 buf=data; 
 msgs[0].addr = AT24C02_ADDR;/*写地址*/
 msgs[0].flags = RT_I2C_WR;
 msgs[0].buf = ® //寄存器
 msgs[0].len = 1;
 
 msgs[1].addr = AT24C02_ADDR;/*写地址*/
 msgs[1].flags = RT_I2C_WR | RT_I2C_NO_START;
 msgs[1].buf = buf;
 msgs[1].len = 1; 
 if( rt_i2c_transfer(bus, msgs, 2) == 2 )
 {
 rt_kprintf("传输值：%02X ",buf[0]);
 return RT_EOK;
 }
 else
 {
 return -RT_ERROR;
 } 
}
uint8_t read_temp_AT24C02(uint8_t *Rdata)
{
 rt_uint8_t Testdata,temp[10];
 rt_uint8_t *AT24C02_data;
 rt_uint8_t status=RT_EOK;
 *AT24C02_data = AT24C02_TEST_DATA; 
 
 status = AT24C02_ReadReg(i2c_bus,0, 1, temp); /* ??????? */
 rt_kprintf("读取的值：%02X ",temp[0]);
 rt_thread_delay(rt_tick_from_millisecond(50)); // FRAM no need.
 status = AT24C02_WriteReg(i2c_bus,1,AT24C02_data); /* ???? */
 rt_thread_delay(rt_tick_from_millisecond(50)); // FRAM no need.
 status = AT24C02_ReadReg(i2c_bus,0, 1, temp); /* ??????? */
 *Rdata = temp[0];
 if(status) rt_kprintf("I2C读写错误 ");
 if(*Rdata==AT24C02_TEST_DATA)
 rt_kprintf("读写成功：%02X ",*Rdata);
 return 0;

}
static void AT24C02_init(const char *name)
{
    rt_uint8_t temp[2] = {0, 0};

/* 查找I2C总线设备,获取I2C总线句柄 */
    i2c_bus = (struct rt_i2c_bus_device *)rt_device_find(name);

if (i2c_bus == RT_NULL)
 {
 rt_kprintf("can't find %s device! ", name);
 }
 else
 {
 rt_kprintf("find %s device! ", name);
 initialized = RT_TRUE;
 }
}

static void i2c_AT24C02_sample(int argc, char *argv[])
{
    uint8_t RSdata;
    char name[RT_NAME_MAX];

if (argc == 2)
    {
        rt_strncpy(name, argv[1], RT_NAME_MAX);
    }
    else
    {
        rt_strncpy(name, AT24C02_I2C_BUS_NAME, RT_NAME_MAX);
    }

if (!initialized)
    {
        /* 初始化 */
        AT24C02_init(name);
    }
    if (initialized)
    {
        /* 读取 */
        read_temp_AT24C02(&RSdata);

rt_kprintf("read 24c02 sensor : %X ", RSdata);
 }
 else
 {
 rt_kprintf("initialize sensor failed! ");
 }
}
/* 导出 msh 命令列表 */
MSH_CMD_EXPORT(i2c_AT24C02_sample, i2c AT24C02 sample);