测试I2C程序出现24C64不可以正常读写是何原因？如何解决？

24C64是16位寻址，读写有稍稍区别

尝试修改了

msh />
msh />at24cxx_eeprom_sample
EEPROM write data is: a,b,c,d,e,f,g,h
EEPROM read data is:

代码如下，不知哪里出了问题。

/* at24cxx设备结构体 /
struct at24cxx_device
{
struct rt_device parent;
struct rt_i2c_bus_device *bus;
};

/* at24cxx设备用户操作配置结构体 /
struct at24cxx_config
{
rt_uint32_t size; //设备的总容量
rt_uint16_t addr; //设备地址
rt_uint16_t flags; //I2C操作标志
};

static rt_size_t at24cxx_read(rt_device_t dev, rt_off_t pos, void buffer, rt_size_t size)
{
struct at24cxx_device at24cxx;
const struct at24cxx_config *cfg;
struct rt_i2c_msg msg[2];
rt_uint8_t mem_addr[2] = {0,};
rt_size_t ret = 0;
RT_ASSERT(dev != 0);

at24cxx = (struct at24cxx_device *) dev;
RT_ASSERT(at24cxx->parent.user_data != 0);
cfg = (const struct at24cxx_config *) at24cxx->parent.user_data;
if(pos >= cfg->size)        //寻址地址超标
{
     return 0;
}
if(pos + size > cfg->size)    // size超标
{
     size = cfg->size - pos;
}
msg[0].addr     = cfg->addr;
msg[0].flags    = cfg->flags | RT_I2C_WR;
if(cfg->size < 257)    // at24c01 at24c02, 一页8字节，寻址地址8位
{
    mem_addr[0] = (rt_uint8_t) pos;
    msg[0].buf     = (rt_uint8_t *) mem_addr;
    msg[0].len     =  1;
}
else    // at24c04/08/16 一页16字节，寻址地址9/10/11位
{
    mem_addr[0]    = (pos >> 8);
    mem_addr[1]    = (rt_uint8_t) pos;
    msg[0].buf    = (rt_uint8_t *) mem_addr;
    msg[0].len     =  2;
}
msg[1].addr     = cfg->addr;
msg[1].flags    = cfg->flags | RT_I2C_RD;
msg[1].buf      = (rt_uint8_t *) buffer;
msg[1].len      = size;
ret = rt_i2c_transfer(at24cxx->bus, msg, 2);
return (ret == 2) ? size : 0;
}

static rt_size_t at24cxx_write(rt_device_t dev, rt_off_t pos, const void buffer, rt_size_t size)
{
struct at24cxx_device at24cxx;
const struct at24cxx_config *cfg;
struct rt_i2c_msg msg[2];
rt_uint8_t mem_addr[2] = {0,};
rt_size_t ret = 0;
RT_ASSERT(dev != 0);

at24cxx = (struct at24cxx_device *) dev;
RT_ASSERT(at24cxx->parent.user_data != 0);
cfg = (const struct at24cxx_config *) at24cxx->parent.user_data;
if(pos > cfg->size)
{
     return 0;
}
if(pos + size > cfg->size)
{
     size = cfg->size - pos;
}
// 写入寻址地址
msg[0].addr     = cfg->addr;
msg[0].flags    = cfg->flags | RT_I2C_WR;
if(cfg->size < 257)    // at24c01 at24c02, 一页8字节，寻址地址8位
{
    mem_addr[0] = (rt_uint8_t) pos;
    msg[0].buf     = (rt_uint8_t *) mem_addr;
    msg[0].len     =  1;
}
else    // at24c04/08/16 一页16字节，寻址地址9/10/11位
{
    mem_addr[0]    = (pos >> 8);
    mem_addr[1]    = (rt_uint8_t) pos;
    msg[0].buf    = (rt_uint8_t *) mem_addr;
    msg[0].len     =  2;
}
// 使用RT_I2C_NO_START，直接写入buffer数据
msg[1].addr     = cfg->addr;
msg[1].flags    = cfg->flags | RT_I2C_WR | RT_I2C_NO_START;
msg[1].buf      = (rt_uint8_t *) buffer;
msg[1].len      = size;
ret = rt_i2c_transfer(at24cxx->bus, msg, 2);
return (ret == 2) ? size : 0;
}

/ RT-Thread device interface /
static rt_err_t at24cxx_init(rt_device_t dev)
{
return RT_EOK;
}

static rt_err_t at24cxx_open(rt_device_t dev, rt_uint16_t oflag)
{
return RT_EOK;
}

static rt_err_t at24cxx_close(rt_device_t dev)
{
return RT_EOK;
}

static rt_err_t at24cxx_control(rt_device_t dev, int cmd, void *args)
{
return RT_EOK;
}

ifdef RT_USING_DEVICE_OPS
/* at24cxx设备操作ops /
const static struct rt_device_ops at24cxx_ops =
{
at24cxx_init,
at24cxx_open,
at24cxx_close,
at24cxx_read,
at24cxx_write,
at24cxx_control
};

endif
/**

@Brief at24cxx设备注册
@param[in] *fm_device_name 设备名称
@param[in] *i2c_bus i2c总线设备名称
@param[in] *user_data 用户数据 at24cxx_config
@Return 函数执行结果
RT_EOK 执行成功
Others 失败
/
rt_err_t at24cxx_register(const char fm_device_name, const char i2c_bus, void user_data)
{
static struct at24cxx_device at24cxx_drv;
struct rt_i2c_bus_device *bus;

bus = rt_i2c_bus_device_find(i2c_bus);
if (bus == RT_NULL)
{

return RT_ENOSYS;
}

at24cxx_drv.bus = bus;
at24cxx_drv.parent.type = RT_Device_Class_Block;

ifdef RT_USING_DEVICE_OPS
at24cxx_drv.parent.ops = &at24cxx_ops;

else
at24cxx_drv.parent.init = at24cxx_init;
at24cxx_drv.parent.open = at24cxx_open;
at24cxx_drv.parent.close = at24cxx_close;
at24cxx_drv.parent.read = at24cxx_read;
at24cxx_drv.parent.write = at24cxx_write;
at24cxx_drv.parent.control = at24cxx_control;

endif
at24cxx_drv.parent.user_data = user_data;

return rt_device_register(&at24cxx_drv.parent, fm_device_name, RT_DEVICE_FLAG_RDWR);
}

static struct at24cxx_config at24c64_config =
{
.size = 8192, // 容量，单位字节
.addr = 0x50, // 注意该地址为没有移位之前的地址不是0xA0
.flags = 0,
};

static int at24cxx_eeprom_sample(void)
{
rt_err_t ret;
rt_uint8_t read_buf[8]={0};
rt_uint8_t write_buf[8] = {‘a’,’b’,’c’,’d’,’e’,’f’,’g’,’h’};

    ret = at24cxx_register("at24c64", "i2c1", &at24c64_config);
    //寻找设备
    rt_device_t at24c64_dev = rt_device_find("at24c64");
if (at24c64_dev == RT_NULL)
{
    rt_kprintf("at24c64 sample run failed! can't find %s device!\n", "at24c64");        
}
rt_device_open(at24c64_dev, RT_DEVICE_FLAG_RDWR);
  if(4 == rt_device_write(at24c64_dev, 0, write_buf, 4))
  {
            rt_kprintf("EEPROM write data is: %c,%c,%c,%c,%c,%c,%c,%c \r\n",write_buf[0],write_buf[1],write_buf[2],write_buf[3],write_buf[4],write_buf[5],write_buf[6],write_buf[7]);
  }
  else
  {
            rt_kprintf("EEPROM write data faild! \n");
  }
  if(4 == rt_device_read(at24c64_dev, 0, read_buf, 4))//0x08地址读数据
  {
            rt_kprintf("EEPROM read data is: %c,%c,%c,%c,%c,%c,%c,%c \r\n",read_buf[0],read_buf[1],read_buf[2],read_buf[3],read_buf[4],read_buf[5],read_buf[6],read_buf[7]);
  }
  else
  {
            rt_kprintf("EEPROM read data faild! \n");
  }
     return 0;
}

一、既然一个可以，一个不行，那就找差别；
1.地址不一致；需要修改地址的相关函数；
2.既然不一样，对应的存储方式是否也不一致；也就是查询、确定地址的方式是否也不一致；
二、建议查询一下对应存储芯片的相关数据手册；