新手学习IIC往AT24C02写入数据失败，不知道怎么解决？【已解决】

发布于 2024-06-27 21:43:06 浏览：453 订阅该版

**问题描述：**
我想向at24c02写入十六进制0x68，然后再从at24c02中读出来。
现在遇到的问题是，读出来的数据一直显示是 0x20003294，目前就是还不知道该怎么去排查问题，没有思路和头绪。
希望大佬们能够指点下思路，万分感谢。

截图及代码如下：

![端口输出截图.png](https://oss-club.rt-thread.org/uploads/20240627/2ed7faee42b69c04dcc0fd9f40cda76c.png.webp)

```c
/*
 * 程序清单：这是一个 iic 设备使用例程
 * 例程导出了 i2c_test 命令到控制终端
 * 命令调用格式：i2c_test
 * 程序功能：向eeprom写入十六进制0x68，然后再读出来
 */

#include <rtthread.h>
#include <rtdevice.h>
#ifdef RT_USING_FINSH
#include <finsh.h>
#endif // RT_USING_FINSH
static const char * i2c_bus_device_name = "i2c1";
static const rt_uint8_t eeprom_addr = 0x50;

rt_err_t i2c_test(void)
{
    struct rt_i2c_bus_device * i2c_device;
    struct rt_i2c_msg msgs[2];
    rt_uint8_t buffer1[1];
    rt_uint8_t buffer2[1];
    i2c_device = rt_i2c_bus_device_find(i2c_bus_device_name);
    if(i2c_device == RT_NULL)
    {
        rt_kprintf("i2c bus device %s not found!\n", i2c_bus_device_name);
        return -RT_ENOSYS;
    }

/* write '0x68' to eeprom */
	buffer1[0] = 0x68;
    msgs[0].addr = eeprom_addr;
    msgs[0].flags = RT_I2C_WR;    // Write to slave
    msgs[0].buf = buffer1;        // eeprom offset
    msgs[0].len = 1;

if (rt_i2c_transfer(i2c_device, &msgs[0], 1) == 1)
{
    rt_kprintf("write eeprom success!\n");
}else{
    rt_kprintf("write eeprom fail!\n");
    return -RT_ERROR;
}

rt_thread_delay(rt_tick_from_millisecond(50));

/* read from eeprom */
    buffer2[0]= 0x00;
    msgs[1].addr  = eeprom_addr;  //读取数据
    msgs[1].flags = RT_I2C_RD;    // Read from slave
    msgs[1].buf   = buffer2;
    msgs[1].len   = 1;

if( rt_i2c_transfer(i2c_device, &msgs[1], 1) == 1 )
{
    rt_kprintf("read eeprom success!\n");
    rt_kprintf("your number is:\n");
    rt_kprintf(" 0x%02X \n ", buffer2);
    rt_kprintf(" \n ");
    return RT_EOK;
}else{
    rt_kprintf("read eeprom fail!\n");
    return -RT_ERROR;
}
}MSH_CMD_EXPORT(i2c_test, i2c_test);
```

4 个回答

crystal266 2024-07-01

嵌入式

JDMT_1321 2024-07-17

这家伙很懒，什么也没写！

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追加回复

YZRD 2024-06-28

这家伙很懒，什么也没写！

JDMT_1321 2024-07-17

这家伙很懒，什么也没写！

crystal266 2024-07-19

嵌入式

JDMT_1321 2024-07-19

这家伙很懒，什么也没写！

请登录后再发布评论，点击登录

追加回复

JDMT_1321 2024-07-18

这家伙很懒，什么也没写！

**通过参考站外大佬的代码，已经成功跑通了
参考链接：https://www.cnblogs.com/silencehuan/p/10944345.html#SnippetTab**

**输出截图：**
![i2c_test3.jpg](https://oss-club.rt-thread.org/uploads/20240718/9c8387f1798ad72abd79aee0e2238b2a.jpg.webp)

**我的代码也放在下面，方便大家参考和指正.**

```c
/*
 * 程序清单：这是一个iic设备使用例程
 * 例程导出了i2c_test3命令到控制终端
 * 命令调用格式：i2c_test3
 * 实现功能：向eeprom写入16进制的HelloRTT,再重读eeprom并以字符输出。
 */

#include <rtthread.h>
#include <rtdevice.h>
static const char * i2c_bus_device_name = "i2c1";
static const rt_uint8_t eeprom_addr = 0x50;      // 1010A2A1A0 - R/W
rt_err_t write_reg(struct rt_i2c_bus_device *bus, rt_uint8_t len, rt_uint8_t *data);
rt_err_t read_regs(struct rt_i2c_bus_device *bus,  rt_uint8_t len,rt_uint8_t *buf);

rt_err_t i2c_test3(void)
{
    struct rt_i2c_bus_device * i2c_device;
    i2c_device = rt_i2c_bus_device_find(i2c_bus_device_name);
    if(i2c_device == RT_NULL)
    {
        rt_kprintf("i2c bus device %s not found!\n", i2c_bus_device_name);
        return -RT_ENOSYS;
    }

rt_size_t i;
	rt_uint8_t send[8] = {0x48,0x65,0x6C,0x6C,0x6F,0x52,0x54,0x54};//HelloRTT
	rt_uint8_t recv[8] = {0};

//step 1: write to eeprom.
	write_reg(i2c_device,8,send);

//step 2: read out from eeprom.
    read_regs(i2c_device,8,recv);
    rt_kprintf("read eeprom at: 0x%02X\n", eeprom_addr);
    rt_kprintf("your data is: \n");
    for(i=0; i<sizeof(recv); i++)
    {
	   rt_kprintf("%c", recv[i]);
    }
    rt_kprintf("\n");
    return RT_EOK;
}MSH_CMD_EXPORT(i2c_test3, i2c_test3);

/* 写eeprom */
static rt_err_t write_reg(struct rt_i2c_bus_device *bus, rt_uint8_t len, rt_uint8_t *data)
{
    struct rt_i2c_msg msgs[2];
	rt_uint8_t buff[1] = {0x00};    //数据在EEPROM上的存储地址
    msgs[0].addr = eeprom_addr;
    msgs[0].flags = RT_I2C_WR;
    msgs[0].buf = buff;
    msgs[0].len = 1;
	msgs[1].addr = eeprom_addr;
    msgs[1].flags = RT_I2C_WR | RT_I2C_NO_START;
    msgs[1].buf = data;
    msgs[1].len = len;
    if (rt_i2c_transfer(bus, msgs, 2) == 2)
    {
	    rt_thread_delay(rt_tick_from_millisecond(10));
        return RT_EOK;
    }else{
	    rt_kprintf("write eeprom fail!\n");
        return -RT_ERROR;
    }
}

/* 读eeprom数据 */
static rt_err_t read_regs(struct rt_i2c_bus_device *bus,rt_uint8_t len,rt_uint8_t *buf)
{
    struct rt_i2c_msg msgs[2];
	rt_uint8_t buff[1] = {0x00};   //数据在EEPROM上的存储地址
    msgs[0].addr = eeprom_addr;
    msgs[0].flags = RT_I2C_WR;
    msgs[0].buf = buff;
    msgs[0].len = 1;
	msgs[1].addr = eeprom_addr;
    msgs[1].flags = RT_I2C_RD;
    msgs[1].buf = buf;
    msgs[1].len = len;
    if (rt_i2c_transfer(bus, msgs, 2) == 2)// 调用I2C设备接口传输数据
    {
        return RT_EOK;
    }else{
		rt_kprintf("read eeprom fail!\n");
        return -RT_ERROR;
    }
}

```

**其它资料：**
EEPROM 写数据流程
第一步，首先是 I2C 的起始信号，接着跟上首字节，也就是我们前边讲的 I2C 的器件地址，并且在读写方向上选择“写”操作。
第二步，发送数据的存储地址。24C02 一共 256 个字节的存储空间，地址从 0x00～0xFF，我们想把数据存储在哪个位置，此刻写的就是哪个地址。
第三步，发送要存储的数据第一个字节、第二个字节？？注意在写数据的过程中，EEPROM 每个字节都会回应一个“应答位 0”，来告诉我们写 EEPROM 数据成功，如果没有回应答位，说明写入不成功。
在写数据的过程中，每成功写入一个字节，EEPROM 存储空间的地址就会自动加 1，当加到 0xFF 后，再写一个字节，地址会溢出又变成了 0x00