No clock I2C STM32L0 - c

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

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.

Answer 2

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.