STM32L072C6T6 LPUART DMA interrupt need Reset MCU to works

[MLam]

Hi everyone,

I'm working on a project with an STM32L072C6T6.

I'm using LPUART1 DMA to get data from my LPUART with interrupt when the bus go idle.

My soft working when, after power on the device, i push the reset button of the MCU. All start correctly.

But when I try turn on my device with only power ON, no interrupt from LPUART occur.

• I have verify my data send on my LPUART bus, it's OK (all data receive and good quality of signal)
• I use DMA for LPUART and USART1 and USART1 works great with every power on method and i have implement LPUART in the same way that USART1
• I have debug the DMA state (HAL_DMA_GetState) and i have seen that when my error occur it's because my DMA state for LPUART stay ready and never become busy like my USART1.
• I check in the same time DMA error (HAL_DMA_GetError) but no error occur

Do you have advice that can put me on a way of a solution ?

I attached CubeMX configuration screen and function that i use to use the LPUART DMA.

Best regards,

Lam

void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size)
{
	if (huart->Instance == LPUART1)
	{
		
		//do something
                printf("LPUART1\r\n");
		
		/* start the DMA again */
		memset(lpuart1_Rx_data, 0, sizeof(lpuart1_Rx_data));
		HAL_UARTEx_ReceiveToIdle_DMA(&hlpuart1, lpuart1_Rx_data, sizeof(lpuart1_Rx_data));
		__HAL_DMA_DISABLE_IT(&hdma_lpuart1_rx, DMA_IT_HT);
 
	}
	
	if (huart->Instance == USART1)
	{
		//printf("INT USART1\r\n");
				
		/* start the DMA again */
		memset(usart1_Rx_data, 0, sizeof(usart1_Rx_data));
		HAL_UARTEx_ReceiveToIdle_DMA(&huart1, usart1_Rx_data, sizeof(usart1_Rx_data));
		__HAL_DMA_DISABLE_IT(&hdma_usart1_rx, DMA_IT_HT);
		
	}
	
}
 
//-------------------------------
 
int main(void)
{
  /* USER CODE BEGIN 1 */
	clear_led();
	
  /* 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_DMA_Init();
  MX_I2C1_Init();
  MX_LPUART1_UART_Init();
  MX_USART1_UART_Init();
  MX_ADC_Init();
  MX_USB_DEVICE_Init();
  MX_LPTIM1_Init();
  MX_RTC_Init();
  /* USER CODE BEGIN 2 */
 
	Init_Context();
 
	//Enable LPUART for RF interrupt
	HAL_UARTEx_ReceiveToIdle_DMA(&hlpuart1, lpuart1_Rx_data, sizeof(lpuart1_Rx_data));
	__HAL_DMA_DISABLE_IT(&hdma_lpuart1_rx, DMA_IT_HT);
 
	//Enable USART1 for Keyboard RFID
	HAL_UARTEx_ReceiveToIdle_DMA(&huart1, usart1_Rx_data, sizeof(usart1_Rx_data));
	__HAL_DMA_DISABLE_IT(&hdma_usart1_rx, DMA_IT_HT);
	
	//verify if DMA is correctly init
	getDMA_init();
	
	//test_main();
	
		
#ifdef DEBUG_PRINT
	printf("*** DEBUG FIRMWARE ***\r\n");
#endif
 
while(1)
{
}
 
}
 
//------------------------------------
 
static void MX_LPUART1_UART_Init(void)
{
 
  /* USER CODE BEGIN LPUART1_Init 0 */
 
  /* USER CODE END LPUART1_Init 0 */
 
  /* USER CODE BEGIN LPUART1_Init 1 */
 
  /* USER CODE END LPUART1_Init 1 */
  hlpuart1.Instance = LPUART1;
  hlpuart1.Init.BaudRate = 9600;
  hlpuart1.Init.WordLength = UART_WORDLENGTH_8B;
  hlpuart1.Init.StopBits = UART_STOPBITS_1;
  hlpuart1.Init.Parity = UART_PARITY_NONE;
  hlpuart1.Init.Mode = UART_MODE_TX_RX;
  hlpuart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  hlpuart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  hlpuart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&hlpuart1) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN LPUART1_Init 2 */
 
  /* USER CODE END LPUART1_Init 2 */
 
}
 
//---------------------------------
 
static void MX_DMA_Init(void)
{
 
  /* DMA controller clock enable */
  __HAL_RCC_DMA1_CLK_ENABLE();
 
  /* DMA interrupt init */
  /* DMA1_Channel2_3_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Channel2_3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);
  /* DMA1_Channel4_5_6_7_IRQn interrupt configuration */
  HAL_NVIC_SetPriority(DMA1_Channel4_5_6_7_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(DMA1_Channel4_5_6_7_IRQn);
 
}
 
//----------------------------
 
void getDMA_init(void)
{
	//Waiting DMA hardware initialization
	uint8_t draw_wait_state = 0;
	uint32_t counter;
	HAL_DMA_StateTypeDef test;
	uint32_t test2;
	test = HAL_DMA_GetState(&hdma_lpuart1_rx);
	printf("dma lpuart1 : %x", test);
	test = HAL_DMA_GetState(&hdma_usart1_rx);
	printf("dma usart1 : %x", test);
	test2 = HAL_DMA_GetError(&hdma_lpuart1_rx);
	printf("dma lpuart1 error : %lu", test2);
	test2 = HAL_DMA_GetError(&hdma_usart1_rx);
	printf("dma usart1 error: %lu", test2);
}

[MLam]

News about my problem,

I have try to get information about my LPUART state. So i use this functions to get informations : HAL_UART_GetState(&hlpuart1) and HAL_UART_GetError(&hlpuart1).

I use this functions after uart init and i ahve this results : lpuart 1 state : 34 lpuart 1 error : 0

I use this just before my function that want to receive and send data throught LPUART1 and i obtain this results : lpuart 1 state : 32 lpuart 1 error : 0

I understand that i have an error on my LPUART1 apparently. But i don't understand the cause and why this occur only sometimes.

I joined below my code to check error.

Do you have advice about this error ?

void getDMA_init(void)
{
	//Waiting DMA hardware initialization
	uint8_t draw_wait_state = 0;
	uint32_t counter;
	HAL_DMA_StateTypeDef test;
	uint32_t test2;
	HAL_UART_StateTypeDef test3;
	test = HAL_DMA_GetState(&hdma_lpuart1_rx);
	printf("dma lpuart1 : %x ", test);
	test = HAL_DMA_GetState(&hdma_usart1_rx);
	printf("dma usart1 : %x ", test);
	test2 = HAL_DMA_GetError(&hdma_lpuart1_rx);
	printf("dma lpuart1 error : %lu ", test2);
	test2 = HAL_DMA_GetError(&hdma_usart1_rx);
	printf("dma usart1 error: %lu \r\n", test2);
	test3 = HAL_UART_GetState(&hlpuart1);
	printf("lpuart 1 state : %lu ",(uint32_t)test3 );
	printf(" lpuart 1 error : %lu \r\n", HAL_UART_GetError(&hlpuart1));
}

[Guenael Cadier]

Dear @MLam​ 

Regarding UART state values you mentioned, i don't think this indicates an error.

32 => 0x20 indicates Initialisation has been done an no TX or RX activity is ongoing. No error reported.

34 => 0x22 indicates Initialization is done, and a RX process is ongoing.

Regarding your problem, when nothing seems to appear on reception side, could you check the LPUART ISR register content when this occurs ? One hypothesis could be that Overrun flag is set, preventing any further reception until it is cleared.

Just an idea ...

Hope this helps

[MLam]

Hello,

Thanks for you return,

I found a solution to solve my problem when my device boot,

if (HAL_UART_GetState(&hlpuart1) == 32)	// on power-on LPUART/DMA meet problem to start interrupt maybe due of power-on of the module connected so we need to reinitialize LPUART and DMA
	{
		HAL_UART_Abort_IT(&hlpuart1);
		HAL_UART_DMAStop(&hlpuart1);
		MX_LPUART1_UART_Init();
		//Enable LPUART for RF interrupt
		HAL_UARTEx_ReceiveToIdle_DMA(&hlpuart1, lpuart1_Rx_data, sizeof(lpuart1_Rx_data));
		__HAL_DMA_DISABLE_IT(&hdma_lpuart1_rx, DMA_IT_HT);
		
	}

I'm agree that not the better solution but that allow my program to receive the frames with interrupt.

Since this time my program has evolve and i start with USART and after LPUART, i don't need to use this code and i don't meet this error.

Best regards,

MLam