无时钟I2C STM32L0

Question

Hi i am currently working on a project where i am using a murata cmwx1zzabz (The module is powered by an STM32L072CZ and an SX1276 transceiver). The goal eventually is to send data from my sensor(VL53L1X) using lorawan to the internet.

So i started using the lorawan stack from ST on my st B-L072Z_LRWAN1 discoveryboard. When i tried to connect the sensor to the proccesor it didn't work.

I then decided to use a "Fresh" STM32cubeMX project where i wanted to make the I2C connection work.

By both of the projects there was nothing but a 330mV dc voltage on the CLK and SDA pins.

I am new to the whole STcube projects so i may be forgetting something obvious. I have been working on this problem for almost 18 hours now and am at this point i am trying to just get the SCL and SDA lines to work.

my code:

int main(void)
{
  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* Configure the system clock */
  SystemClock_Config();

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();
  MX_RTC_Init();
  MX_I2C1_Init();
  /* USER CODE BEGIN 2 */
  uint8_t buf = 25;                                             // random value just to see if i can get the SCL and SDA lines to change  from value 
  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */

    HAL_I2C_Master_Transmit(&hi2c1,0x18<<1,&buf,2,100000);
    HAL_Delay(1000);

    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}

---

static void MX_I2C1_Init(void)
{

  /* USER CODE BEGIN I2C1_Init 0 */

  /* USER CODE END I2C1_Init 0 */

  /* USER CODE BEGIN I2C1_Init 1 */

  /* USER CODE END I2C1_Init 1 */
  hi2c1.Instance = I2C1;
  hi2c1.Init.Timing = 0x00707CBB;
  hi2c1.Init.OwnAddress1 = 0;
  hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c1.Init.OwnAddress2 = 0;
  hi2c1.Init.OwnAddress2Masks = I2C_OA2_NOMASK;
  hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  if (HAL_I2C_Init(&hi2c1) != HAL_OK)
  {
    Error_Handler();
  }

}

---

HAL_StatusTypeDef HAL_I2C_Init(I2C_HandleTypeDef *hi2c)
{
  /* Check the I2C handle allocation */
  if (hi2c == NULL)
  {
    return HAL_ERROR;
  }

  /* Check the parameters */
  assert_param(IS_I2C_ALL_INSTANCE(hi2c->Instance));
  assert_param(IS_I2C_OWN_ADDRESS1(hi2c->Init.OwnAddress1));
  assert_param(IS_I2C_ADDRESSING_MODE(hi2c->Init.AddressingMode));
  assert_param(IS_I2C_DUAL_ADDRESS(hi2c->Init.DualAddressMode));
  assert_param(IS_I2C_OWN_ADDRESS2(hi2c->Init.OwnAddress2));
  assert_param(IS_I2C_OWN_ADDRESS2_MASK(hi2c->Init.OwnAddress2Masks));
  assert_param(IS_I2C_GENERAL_CALL(hi2c->Init.GeneralCallMode));
  assert_param(IS_I2C_NO_STRETCH(hi2c->Init.NoStretchMode));

  if (hi2c->State == HAL_I2C_STATE_RESET)
  {
    /* Allocate lock resource and initialize it */
    hi2c->Lock = HAL_UNLOCKED;

#if (USE_HAL_I2C_REGISTER_CALLBACKS == 1)
    /* Init the I2C Callback settings */
    hi2c->MasterTxCpltCallback = HAL_I2C_MasterTxCpltCallback; /* Legacy weak MasterTxCpltCallback */
    hi2c->MasterRxCpltCallback = HAL_I2C_MasterRxCpltCallback; /* Legacy weak MasterRxCpltCallback */
    hi2c->SlaveTxCpltCallback  = HAL_I2C_SlaveTxCpltCallback;  /* Legacy weak SlaveTxCpltCallback  */
    hi2c->SlaveRxCpltCallback  = HAL_I2C_SlaveRxCpltCallback;  /* Legacy weak SlaveRxCpltCallback  */
    hi2c->ListenCpltCallback   = HAL_I2C_ListenCpltCallback;   /* Legacy weak ListenCpltCallback   */
    hi2c->MemTxCpltCallback    = HAL_I2C_MemTxCpltCallback;    /* Legacy weak MemTxCpltCallback    */
    hi2c->MemRxCpltCallback    = HAL_I2C_MemRxCpltCallback;    /* Legacy weak MemRxCpltCallback    */
    hi2c->ErrorCallback        = HAL_I2C_ErrorCallback;        /* Legacy weak ErrorCallback        */
    hi2c->AbortCpltCallback    = HAL_I2C_AbortCpltCallback;    /* Legacy weak AbortCpltCallback    */
    hi2c->AddrCallback         = HAL_I2C_AddrCallback;         /* Legacy weak AddrCallback         */

    if (hi2c->MspInitCallback == NULL)
    {
      hi2c->MspInitCallback = HAL_I2C_MspInit; /* Legacy weak MspInit  */
    }

    /* Init the low level hardware : GPIO, CLOCK, CORTEX...etc */
    hi2c->MspInitCallback(hi2c);
#else
    /* Init the low level hardware : GPIO, CLOCK, CORTEX...etc */
    HAL_I2C_MspInit(hi2c);
#endif /* USE_HAL_I2C_REGISTER_CALLBACKS */
  }

  hi2c->State = HAL_I2C_STATE_BUSY;

  /* Disable the selected I2C peripheral */
  __HAL_I2C_DISABLE(hi2c);

  /*---------------------------- I2Cx TIMINGR Configuration ------------------*/
  /* Configure I2Cx: Frequency range */
  hi2c->Instance->TIMINGR = hi2c->Init.Timing & TIMING_CLEAR_MASK;

  /*---------------------------- I2Cx OAR1 Configuration ---------------------*/
  /* Disable Own Address1 before set the Own Address1 configuration */
  hi2c->Instance->OAR1 &= ~I2C_OAR1_OA1EN;

  /* Configure I2Cx: Own Address1 and ack own address1 mode */
  if (hi2c->Init.AddressingMode == I2C_ADDRESSINGMODE_7BIT)
  {
    hi2c->Instance->OAR1 = (I2C_OAR1_OA1EN | hi2c->Init.OwnAddress1);
  }
  else /* I2C_ADDRESSINGMODE_10BIT */
  {
    hi2c->Instance->OAR1 = (I2C_OAR1_OA1EN | I2C_OAR1_OA1MODE | hi2c->Init.OwnAddress1);
  }

  /*---------------------------- I2Cx CR2 Configuration ----------------------*/
  /* Configure I2Cx: Addressing Master mode */
  if (hi2c->Init.AddressingMode == I2C_ADDRESSINGMODE_10BIT)
  {
    hi2c->Instance->CR2 = (I2C_CR2_ADD10);
  }
  /* Enable the AUTOEND by default, and enable NACK (should be disable only during Slave process */
  hi2c->Instance->CR2 |= (I2C_CR2_AUTOEND | I2C_CR2_NACK);

  /*---------------------------- I2Cx OAR2 Configuration ---------------------*/
  /* Disable Own Address2 before set the Own Address2 configuration */
  hi2c->Instance->OAR2 &= ~I2C_DUALADDRESS_ENABLE;

  /* Configure I2Cx: Dual mode and Own Address2 */
  hi2c->Instance->OAR2 = (hi2c->Init.DualAddressMode | hi2c->Init.OwnAddress2 | (hi2c->Init.OwnAddress2Masks << 8));

  /*---------------------------- I2Cx CR1 Configuration ----------------------*/
  /* Configure I2Cx: Generalcall and NoStretch mode */
  hi2c->Instance->CR1 = (hi2c->Init.GeneralCallMode | hi2c->Init.NoStretchMode);

  /* Enable the selected I2C peripheral */
  __HAL_I2C_ENABLE(hi2c);

  hi2c->ErrorCode = HAL_I2C_ERROR_NONE;
  hi2c->State = HAL_I2C_STATE_READY;
  hi2c->PreviousState = I2C_STATE_NONE;
  hi2c->Mode = HAL_I2C_MODE_NONE;

  return HAL_OK;
}
_________

---

void HAL_I2C_MspInit(I2C_HandleTypeDef* hi2c)
{

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

  /* USER CODE END I2C1_MspInit 0 */

    __HAL_RCC_GPIOB_CLK_ENABLE();
    /**I2C1 GPIO Configuration    
    PB9     ------> I2C1_SDA
    PB8     ------> I2C1_SCL 
    */
    GPIO_InitStruct.Pin = GPIO_PIN_9;
    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);

    GPIO_InitStruct.Pin = 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();
  /* USER CODE BEGIN I2C1_MspInit 1 */

  /* USER CODE END I2C1_MspInit 1 */
  }

}

---

PS: i have tried a mbed example of the sensor on this discovery board and it works correctly.

Answer 1

I'm not familiar with the STM32L0. But I looked at my STM32L4 examples. One thing in my L4 I2C example that is missing from your code is configuring the I2C Clock source in HAL_I2C_MspInit()

/*##-1- Configure the I2C clock source. The clock is derived from the SYSCLK #*/
RCC_PeriphCLKInitStruct.PeriphClockSelection = RCC_PERIPHCLK_I2Cx;
RCC_PeriphCLKInitStruct.I2c3ClockSelection = RCC_I2CxCLKSOURCE_SYSCLK;
HAL_RCCEx_PeriphCLKConfig(&RCC_PeriphCLKInitStruct);

If that is not applicable or doesn't help then I suggest you download the STM32CubeL0 package which should include an I2C example, maybe even for you specific board.

Answer 2

Thanks everybody for the help.

i found out what the problem of my code was.

in the STM32L0xx_hal_msp.c file there is a function called void HAL_I2C_MspInit(I2C_HandleTypeDef* hi2c) In this function the SCL and SDA pins are declared

__HAL_RCC_GPIOB_CLK_ENABLE();
/**I2C1 GPIO Configuration    
PB9     ------> I2C1_SDA
PB8     ------> I2C1_SCL 
*/
GPIO_InitStruct.Pin = GPIO_PIN_9|GPIO_PIN_8;
GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;         // standard GPIO_MODE_AF_OD => GPIO_MODE_AF_PP (open drain mode to push pull mode )
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();

Changing the mode of the pins fixed the problem.