STM3210E-EVAL won't receive UART

[Smdeint]

Hello, I'm building a communication between two devices an Arduino Mega 2560 and STM3210E-EVAL. For the communication I need to use RS232. In between the two devices I use the MAX232. I got it working one way where the STM32 sends 1 byte to the Arduino Mega. Next I wanted to test communication to the STM32 by sending the character 'X', but the STM32 doesn't receive the data. I use the simple polling method to receive the UART data.

This is how my main function looks like. For the printf() I use UART1.

uint8_t rx_data[10];

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_ADC1_Init();
  MX_FSMC_Init();
  MX_USART2_UART_Init();
  MX_USB_PCD_Init();
  MX_USART1_UART_Init();
  /* USER CODE BEGIN 2 */

  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */

  while (1)
  {
    /* USER CODE END WHILE */

    /* USER CODE BEGIN 3 */

	  if (HAL_UART_Receive(&huart2, rx_data, 10, 1000) == HAL_OK) {
		  printf("Data");
	  } else {
		  printf("No Data");
	  }

	  HAL_Delay(1000);
  }
  /* USER CODE END 3 */
}

This is how UART2 is initialized:

  /* USER CODE END USART2_Init 1 */
  huart2.Instance = USART2;
  huart2.Init.BaudRate = 115200;
  huart2.Init.WordLength = UART_WORDLENGTH_8B;
  huart2.Init.StopBits = UART_STOPBITS_1;
  huart2.Init.Parity = UART_PARITY_NONE;
  huart2.Init.Mode = UART_MODE_TX_RX;
  huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart2.Init.OverSampling = UART_OVERSAMPLING_16;

I read somewhere that the problem could be in the hal_msp.c file so here is the init of UART in that file.

/**
* @brief UART MSP Initialization
* This function configures the hardware resources used in this example
* @PAram huart: UART handle pointer
* @retval None
*/
void HAL_UART_MspInit(UART_HandleTypeDef* huart)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
  if(huart->Instance==USART1)
  {
  /* USER CODE BEGIN USART1_MspInit 0 */

  /* USER CODE END USART1_MspInit 0 */
    /* Peripheral clock enable */
    __HAL_RCC_USART1_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**USART1 GPIO Configuration
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX
    */
    GPIO_InitStruct.Pin = USART1_TX_Pin|USART1_RX_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* USER CODE BEGIN USART1_MspInit 1 */

  /* USER CODE END USART1_MspInit 1 */
  }
  else if(huart->Instance==USART2)
  {
  /* USER CODE BEGIN USART2_MspInit 0 */

  /* USER CODE END USART2_MspInit 0 */
    /* Peripheral clock enable */
    __HAL_RCC_USART2_CLK_ENABLE();

    __HAL_RCC_GPIOA_CLK_ENABLE();
    /**USART2 GPIO Configuration
    PA1     ------> USART2_RTS
    PA2     ------> USART2_TX
    PA3     ------> USART2_RX
    */
    GPIO_InitStruct.Pin = USART2_RTS_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(USART2_RTS_GPIO_Port, &GPIO_InitStruct);

    GPIO_InitStruct.Pin = USART2_TX_Pin|USART2_RX_Pin;
    GPIO_InitStruct.Mode = GPIO_MODE_AF_PP;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* USER CODE BEGIN USART2_MspInit 1 */

  /* USER CODE END USART2_MspInit 1 */
  }

}

/**
* @brief UART MSP De-Initialization
* This function freeze the hardware resources used in this example
* @PAram huart: UART handle pointer
* @retval None
*/
void HAL_UART_MspDeInit(UART_HandleTypeDef* huart)
{
  if(huart->Instance==USART1)
  {
  /* USER CODE BEGIN USART1_MspDeInit 0 */

  /* USER CODE END USART1_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_USART1_CLK_DISABLE();

    /**USART1 GPIO Configuration
    PA9     ------> USART1_TX
    PA10     ------> USART1_RX
    */
    HAL_GPIO_DeInit(GPIOA, USART1_TX_Pin|USART1_RX_Pin);

  /* USER CODE BEGIN USART1_MspDeInit 1 */

  /* USER CODE END USART1_MspDeInit 1 */
  }
  else if(huart->Instance==USART2)
  {
  /* USER CODE BEGIN USART2_MspDeInit 0 */

  /* USER CODE END USART2_MspDeInit 0 */
    /* Peripheral clock disable */
    __HAL_RCC_USART2_CLK_DISABLE();

    /**USART2 GPIO Configuration
    PA1     ------> USART2_RTS
    PA2     ------> USART2_TX
    PA3     ------> USART2_RX
    */
    HAL_GPIO_DeInit(GPIOA, USART2_RTS_Pin|USART2_TX_Pin|USART2_RX_Pin);

  /* USER CODE BEGIN USART2_MspDeInit 1 */

  /* USER CODE END USART2_MspDeInit 1 */
  }

}

In the attached images you can see the configuration.

If someone knows what is wrong let me know, because I'm stuck and I don't have that much experience to debug this problem. If you need more info just let me know.

[Tesla DeLorean · Accepted solution]

If you want one character, try doing that, and not 10

Perhaps try a loop-back confirm if its a reception issue (ie RS232 DB9 Pin 2 to Pin 3), or a signal issue. Send and receive back.

Show wiring

Put a scope on the signal, check USART2->SR for any sticky reception errors

Been an age but doesn't the STM32F1 USART_RX pin need to be in INPUT Mode, not PP AF ?

[Smdeint]

I got it working by changing the USART2_RX pin to INPUT Mode. First I could not change the mode. I had to disable FSMC somehow the pins are connected to each other. Maybe you know why this is?