15 使用rtt_studio开发I2C碰到的问题

发布于 2020-09-14 16:30:05 浏览：2199 订阅该版

使用i2c设备时可以查询到设备，但是rt_i2c_transfer出错，错误码为-1.利用逻辑分析仪抓包时，时钟线应该是有问题，这是指引脚和i2c初始化时出错吗？初始化代码是用cube mx直接生成的。具体代码如下：
```
static void MX_I2C2_Init(void)
{

hi2c2.Instance = I2C2;
  hi2c2.Init.ClockSpeed = 100000;
  hi2c2.Init.DutyCycle = I2C_DUTYCYCLE_2;
  hi2c2.Init.OwnAddress1 = 0;
  hi2c2.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c2.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c2.Init.OwnAddress2 = 0;
  hi2c2.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c2.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  if (HAL_I2C_Init(&hi2c2) != HAL_OK)
  {
    rt_kprintf("i2c init error");
    Error_Handler();
  }
  /** Configure Analogue filter
  */
  if (HAL_I2CEx_ConfigAnalogFilter(&hi2c2, I2C_ANALOGFILTER_ENABLE) != HAL_OK)
  {
    rt_kprintf("i2c filter error");
    Error_Handler();
  }
  /** Configure Digital filter
  */
  if (HAL_I2CEx_ConfigDigitalFilter(&hi2c2, 0) != HAL_OK)
  {
    rt_kprintf("i2c digit filter error");
    Error_Handler();
  }
  /* USER CODE BEGIN I2C2_Init 2 */

/* USER CODE END I2C2_Init 2 */

}
void HAL_I2C_MspInit(I2C_HandleTypeDef* hi2c)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

if(hi2c->Instance==I2C2)
  {
  /* USER CODE BEGIN I2C2_MspInit 0 */

/* USER CODE END I2C2_MspInit 0 */

__HAL_RCC_GPIOH_CLK_ENABLE();
    /**I2C2 GPIO Configuration
    PH5     ------> I2C2_SDA
    PH4     ------> I2C2_SCL
    */
    GPIO_InitStruct.Pin = GPIO_PIN_4|GPIO_PIN_5;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
    GPIO_InitStruct.Pull = GPIO_NOPULL;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF4_I2C2;
    HAL_GPIO_Init(GPIOH, &GPIO_InitStruct);

/* Peripheral clock enable */
    __HAL_RCC_I2C2_CLK_ENABLE();
  /* USER CODE BEGIN I2C2_MspInit 1 */

/* USER CODE END I2C2_MspInit 1 */
  }

}
写寄存器函数如下
/* 写传感器寄存器 */
static rt_err_t write_reg(struct rt_i2c_bus_device *bus, rt_uint8_t reg, rt_uint32_t data)
{
    rt_uint8_t buf[4];
    struct rt_i2c_msg msgs;

buf[0] = reg; //cmd
    buf[1] = (rt_uint8_t)data>>16;
    buf[2] = (rt_uint8_t)data>>8;
    buf[3] = (rt_uint8_t)data;

msgs.addr = ADS_ADDR;
    msgs.flags = RT_I2C_WR;
    msgs.buf = buf;
    msgs.len = 4;

/* 调用I2C设备接口传输数据 */
    if (rt_i2c_transfer(bus, &msgs, 1) == 1)
    {
        return RT_EOK;
    }
    else
    {
        return -RT_ERROR;
    }
}
/* board.h 中如下 */
#define BSP_USING_I2C2
#ifdef BSP_USING_I2C2
#define BSP_I2C2_SCL_PIN    GET_PIN(H, 4)
#define BSP_I2C2_SDA_PIN    GET_PIN(H, 5)
#endif
```
![微信截图_20200914162531.png](/uploads/20200914/f14f653b915b7806879ba0382071a393.png)