STM32F746G-DISCO USART1 TX works but RX not receiving (ST-Link VCP)

[kiwiosek2007]

Hi,

On STM32F746G-DISCO board I have a problem with USART1 (ST-Link VCP):

- TX (PA9) works fine – I can send messages
- RX (PB7) doesn't receive any characters and I think the board is not waiting for commands 
Tested both polling (HAL_UART_Receive) and interrupt mode (HAL_UART_Receive_IT). Pins are configured correctly.

Did anyone have similar issue on this board? Any ideas what can block RX?

Thanks!

  /* USER CODE BEGIN 2 */
  HAL_UART_Transmit(&huart1, (uint8_t*)"Connected\r\n", 11, 100);
  HAL_Delay(100);
  HAL_UART_Receive_IT(&huart1, &rxByte, 1);
  /* USER CODE END 2 */

/* USER CODE BEGIN 4 */
void ProcessCommand(char *cmd);
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
    if (huart->Instance == USART1)
    {
        if (rxByte == '\n' || rxByte == '\r')
        {
            if (rxIndex > 0)
            {
                rxBuffer[rxIndex] = '\0';           // zakończenie stringa
                ProcessCommand((char*)rxBuffer);
                rxIndex = 0;
            }
        }
        else
        {
            if (rxIndex < 15)                       // zabezpieczenie przed przepełnieniem
            {
                rxBuffer[rxIndex++] = rxByte;
            }
            else
            {
                rxIndex = 0;                        // reset przy zbyt długiej komendzie
            }
        }

        HAL_UART_Receive_IT(&huart1, &rxByte, 1);   // restart przerwania
    }
}

void ProcessCommand(char *cmd)
{
    // Usunięcie ewentualnego \r na końcu
    cmd[strcspn(cmd, "\r")] = '\0';

    if (strcmp(cmd, "system-stat-1") == 0)
    {
        sys_status = 1;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: system-stat-1\r\n", 19, 100);
    }
    else if (strcmp(cmd, "system-stat-2") == 0)
    {
        sys_status = 2;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: system-stat-2\r\n", 19, 100);
    }
    else if (strcmp(cmd, "system-stat-3") == 0)
    {
        sys_status = 3;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: system-stat-3\r\n", 19, 100);
    }
    else if (strcmp(cmd, "net-stat-1") == 0)
    {
        net_status = 1;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: net-stat-1\r\n", 16, 100);
    }
    else if (strcmp(cmd, "net-stat-2") == 0)
    {
        net_status = 2;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: net-stat-2\r\n", 16, 100);
    }
    else if (strcmp(cmd, "net-stat-3") == 0)
    {
        net_status = 3;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: net-stat-3\r\n", 16, 100);
    }
    else if (strcmp(cmd, "sensor-stat-1") == 0)
    {
        sensor_status = 1;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: sensor-stat-1\r\n", 19, 100);
    }
    else if (strcmp(cmd, "sensor-stat-2") == 0)
    {
        sensor_status = 2;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: sensor-stat-2\r\n", 19, 100);
    }
    else if (strcmp(cmd, "sensor-stat-3") == 0)
    {
        sensor_status = 3;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: sensor-stat-3\r\n", 19, 100);
    }
    else if (strcmp(cmd, "alarm-stat-1") == 0)
    {
        alarm_status = 1;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: alarm-stat-1\r\n", 18, 100);
    }
    else if (strcmp(cmd, "alarm-stat-2") == 0)
    {
        alarm_status = 2;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: alarm-stat-2\r\n", 18, 100);
    }
    else if (strcmp(cmd, "alarm-stat-3") == 0)
    {
        alarm_status = 3;
        HAL_UART_Transmit(&huart1, (uint8_t*)"OK: alarm-stat-3\r\n", 18, 100);
    }
    else
    {
        HAL_UART_Transmit(&huart1, (uint8_t*)"Nieprawidlowa komenda\r\n", 22, 100);
    }
}

  /* USART1 TX = PA9, RX = PB7 */
  GPIO_InitStruct.Pin       = GPIO_PIN_9;
  GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull      = GPIO_NOPULL;
  GPIO_InitStruct.Speed     = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  GPIO_InitStruct.Pin       = GPIO_PIN_7;
  GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull      = GPIO_NOPULL;
  GPIO_InitStruct.Speed     = GPIO_SPEED_FREQ_VERY_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART1;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);

  /* USER CODE END USART1_Init 1 */
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  huart1.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart1.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart1) != HAL_OK)
  {
    Error_Handler();
  }

[kiwiosek2007 · Accepted solution]

Magicaly it started worked.
I turn on the usart global interrupt beacause somehow it turned off and I didn't saw it.