STM32 USART LL Interrupt

Question

I am using the NUCLEO-L053R8 board to communicate with a peripheral over USART. I started to send commands which are working fine. The peripheral transmits the data to the corresponding device. After a successfull send command the device answers with a message on the Rx line, which looks like this.

Now i want to receive these two messages and analyze them. Therefore i tried to use the Interrupt function.

I initialized my USART with CubeMX like this:

static void MX_USART1_UART_Init(void)
{

  /* USER CODE BEGIN USART1_Init 0 */

  /* USER CODE END USART1_Init 0 */

  LL_USART_InitTypeDef USART_InitStruct = {0};

  LL_GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* Peripheral clock enable */
  LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_USART1);

  LL_IOP_GRP1_EnableClock(LL_IOP_GRP1_PERIPH_GPIOA);
  /**USART1 GPIO Configuration
  PA9   ------> USART1_TX
  PA10   ------> USART1_RX
  */
  GPIO_InitStruct.Pin = LL_GPIO_PIN_9;
  GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
  GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
  GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
  GPIO_InitStruct.Alternate = LL_GPIO_AF_4;
  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  GPIO_InitStruct.Pin = LL_GPIO_PIN_10;
  GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;
  GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;
  GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;
  GPIO_InitStruct.Alternate = LL_GPIO_AF_4;
  LL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* USART1 interrupt Init */
  NVIC_SetPriority(USART1_IRQn, 0);
  NVIC_EnableIRQ(USART1_IRQn);

  /* USER CODE BEGIN USART1_Init 1 */

  /* USER CODE END USART1_Init 1 */
  USART_InitStruct.BaudRate = 115200;
  USART_InitStruct.DataWidth = LL_USART_DATAWIDTH_8B;
  USART_InitStruct.StopBits = LL_USART_STOPBITS_1;
  USART_InitStruct.Parity = LL_USART_PARITY_NONE;
  USART_InitStruct.TransferDirection = LL_USART_DIRECTION_TX_RX;
  USART_InitStruct.HardwareFlowControl = LL_USART_HWCONTROL_NONE;
  USART_InitStruct.OverSampling = LL_USART_OVERSAMPLING_16;
  LL_USART_Init(USART1, &USART_InitStruct);
  LL_USART_ConfigAsyncMode(USART1);
  LL_USART_Enable(USART1);
  /* USER CODE BEGIN USART1_Init 2 */

  /* USER CODE END USART1_Init 2 */

}

In my stm32l0xx_it.c file i changed the ISR like this:

void USART1_IRQHandler(void)
{
  /* USER CODE BEGIN USART1_IRQn 0 */

  /* USER CODE END USART1_IRQn 0 */

  /* USER CODE BEGIN USART1_IRQn 1 */
    
      /* Check RXNE flag value in SR register */
  if(LL_USART_IsActiveFlag_RXNE(USART1) && LL_USART_IsEnabledIT_RXNE(USART1))
  {
    /* RXNE flag will be cleared by reading of DR register (done in call) */
    /* Call function in charge of handling Character reception */
    USART_CharReception_Callback();
  }
  /* USER CODE END USART1_IRQn 1 */
}

The Callback is just a prototype for the beginning.

void USART_CharReception_Callback()
{
    Thyone_ans[k] = LL_USART_ReceiveData8(USART1);
    k++;
}

When i debug my programm the ISR never fires, but with my logic analyzer i see data on the Rx line. Is there any problem with my IRQHandler?

I found the Problem, it works now. I enabled LL_USART_EnableIT_RXNE(USART1); which starts the interrupt. Whats the difference to NVIC_EnableIRQ(USART1_IRQn);? — Walter Nazarenus, Nov 03 '20 at 13:59
yes the problem was that. you enable the IRQ for usart, but for which usart function ? you have to specify for which event. end of a transmission, reception (your case), parity error, cts interrupt .... — Tirdad Sadri Nejad, Nov 08 '20 at 08:29

STM32 USART LL Interrupt

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