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I2C DMA Does Not Transmit

Question asked by t w on Nov 6, 2017

Hello, I'm working to add DMA capabilities to an I2C library I've been working on, and I've been having a couple issues getting DMA integrated.  I am using a ST32F4 Discovery board (F407VGT6), and I've configured the I2C/DMA using the CubeMX tool.  The MspInit function that was generated is below: 

 

void HAL_I2C_MspInit(I2C_HandleTypeDef* hi2c)
{

  GPIO_InitTypeDef GPIO_InitStruct;
  if(hi2c->Instance==I2C1)
  {
  /* USER CODE BEGIN I2C1_MspInit 0 */

  /* USER CODE END I2C1_MspInit 0 */
 
    /**I2C1 GPIO Configuration   
    PB7     ------> I2C1_SDA
    PB8     ------> I2C1_SCL
    */

    GPIO_InitStruct.Pin = GPIO_PIN_7|GPIO_PIN_8;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
    GPIO_InitStruct.Pull = GPIO_PULLUP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
    GPIO_InitStruct.Alternate = GPIO_AF4_I2C1;
    HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

    /* Peripheral clock enable */
    __HAL_RCC_I2C1_CLK_ENABLE();
 
    /* I2C1 DMA Init */
    /* I2C1_TX Init */
    hdma_i2c1_tx.Instance = DMA1_Stream6;
    hdma_i2c1_tx.Init.Channel = DMA_CHANNEL_1;
    hdma_i2c1_tx.Init.Direction = DMA_MEMORY_TO_PERIPH;
    hdma_i2c1_tx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_i2c1_tx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_i2c1_tx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_i2c1_tx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_i2c1_tx.Init.Mode = DMA_NORMAL;
    hdma_i2c1_tx.Init.Priority = DMA_PRIORITY_LOW;
    hdma_i2c1_tx.Init.FIFOMode = DMA_FIFOMODE_DISABLE;
    if (HAL_DMA_Init(&hdma_i2c1_tx) != HAL_OK)
    {
      _Error_Handler(__FILE__, __LINE__);
    }

    __HAL_LINKDMA(hi2c,hdmatx,hdma_i2c1_tx);

    /* I2C1_RX Init */
    hdma_i2c1_rx.Instance = DMA1_Stream5;
    hdma_i2c1_rx.Init.Channel = DMA_CHANNEL_1;
    hdma_i2c1_rx.Init.Direction = DMA_PERIPH_TO_MEMORY;
    hdma_i2c1_rx.Init.PeriphInc = DMA_PINC_DISABLE;
    hdma_i2c1_rx.Init.MemInc = DMA_MINC_ENABLE;
    hdma_i2c1_rx.Init.PeriphDataAlignment = DMA_PDATAALIGN_BYTE;
    hdma_i2c1_rx.Init.MemDataAlignment = DMA_MDATAALIGN_BYTE;
    hdma_i2c1_rx.Init.Mode = DMA_NORMAL;
    hdma_i2c1_rx.Init.Priority = DMA_PRIORITY_LOW;
    hdma_i2c1_rx.Init.FIFOMode = DMA_FIFOMODE_ENABLE;
    hdma_i2c1_rx.Init.FIFOThreshold = DMA_FIFO_THRESHOLD_FULL;
    hdma_i2c1_rx.Init.MemBurst = DMA_MBURST_SINGLE;
    hdma_i2c1_rx.Init.PeriphBurst = DMA_PBURST_SINGLE;
    if (HAL_DMA_Init(&hdma_i2c1_rx) != HAL_OK)
    {
      _Error_Handler(__FILE__, __LINE__);
    }

    __HAL_LINKDMA(hi2c,hdmarx,hdma_i2c1_rx);

  /* USER CODE BEGIN I2C1_MspInit 1 */

  /* USER CODE END I2C1_MspInit 1 */
  }

}

 

The MX_GPIO_Init, MX_I2C_Init, and MX_DMA_Init functions all appear in main.c: 

/** System Clock Configuration
*/

void SystemClock_Config(void)
{

  RCC_OscInitTypeDef RCC_OscInitStruct;
  RCC_ClkInitTypeDef RCC_ClkInitStruct;

    /**Configure the main internal regulator output voltage
    */

  __HAL_RCC_PWR_CLK_ENABLE();

  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

    /**Initializes the CPU, AHB and APB busses clocks
    */

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = 16;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_NONE;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**Initializes the CPU, AHB and APB busses clocks
    */

  RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
                              |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_HSI;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;

  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_0) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

    /**Configure the Systick interrupt time
    */

  HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);

    /**Configure the Systick
    */

  HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);

  /* SysTick_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}

/* I2C1 init function */
static void MX_I2C1_Init(void)
{

  hi2c1.Instance = I2C1;
  hi2c1.Init.ClockSpeed = 100000;
  hi2c1.Init.DutyCycle = I2C_DUTYCYCLE_2;
  hi2c1.Init.OwnAddress1 = 0;
  hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c1.Init.OwnAddress2 = 0;
  hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  if (HAL_I2C_Init(&hi2c1) != HAL_OK)
  {
    _Error_Handler(__FILE__, __LINE__);
  }

}

/**
  * Enable DMA controller clock
  */

static void MX_DMA_Init(void)
{
  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();

  /* DMA interrupt init */
  /* DMA1_Stream5_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream5_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream5_IRQn);
  /* DMA1_Stream6_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Stream6_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Stream6_IRQn);

}

/** Pinout Configuration
*/

static void MX_GPIO_Init(void)
{

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOB_CLK_ENABLE();

}


And I am invoking the HAL_I2C_Master_Transmit_DMA() function as follows: 

 

     while((i2cError = HAL_I2C_Master_Transmit_DMA(&hi2c1, DEV_ADDRESS, &sendData, 1)) != HAL_OK){
         i2cError = HAL_I2C_GetError(&hi2c1);
         if (i2cError != HAL_I2C_ERROR_AF){
                return i2cError;
         }
     }

 

However, nothing appears on my scope when the Start bit is set in CR1 for I2C1.  Why could this be?  I have had success in communicating with this sensor using standard blocking I2C.

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