Hello, so I was originally using printf with uart3, and that seemed to work fine. The characters were being printed as expected on a PuTTY terminal that I was using. I was using the following code:
/* USER CODE BEGIN PV */
UART_HandleTypeDef *uartHandlerDebug = &huart3; // UART bank used for communication with computer for debugging
/* USER CODE END PV */
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 */
setvbuf(stdout, NULL, _IONBF, 0); //! Disables buffering for stdout
HAL_Delay(1000); // Allow previous code to be erased
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_USART3_UART_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
/*
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
printf("Hello!\r\n");
HAL_Delay(1000);
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief USART2 Initialization Function
* None
* @retval None
*/
static void MX_USART2_UART_Init(void)
{
/* USER CODE BEGIN USART2_Init 0 */
/* USER CODE END USART2_Init 0 */
/* USER CODE BEGIN USART2_Init 1 */
/* USER CODE END USART2_Init 1 */
huart2.Instance = USART2;
huart2.Init.BaudRate = 1000000;
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;
huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART2_Init 2 */
/* USER CODE END USART2_Init 2 */
}
/**
* @brief USART3 Initialization Function
* None
* @retval None
*/
static void MX_USART3_UART_Init(void)
{
/* USER CODE BEGIN USART3_Init 0 */
/* USER CODE END USART3_Init 0 */
/* USER CODE BEGIN USART3_Init 1 */
/* USER CODE END USART3_Init 1 */
huart3.Instance = USART3;
huart3.Init.BaudRate = 1000000; //MODIFY THIS
huart3.Init.WordLength = UART_WORDLENGTH_8B;
huart3.Init.StopBits = UART_STOPBITS_1;
huart3.Init.Parity = UART_PARITY_NONE;
huart3.Init.Mode = UART_MODE_TX_RX;
huart3.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart3.Init.OverSampling = UART_OVERSAMPLING_16;
huart3.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart3.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart3) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART3_Init 2 */
/* USER CODE END USART3_Init 2 */
/* USER CODE BEGIN 4 */
/**
* @brief Print the characters to UART (printf).
* @retval int
*/
#ifdef __GNUC__
/* With GCC, small printf (option LD Linker->Libraries->Small printf
set to 'Yes') calls __io_putchar() */
int __io_putchar(int ch)
#else
int fputc(int ch, FILE *f)
#endif /* __GNUC__ */
{
/* Place your implementation of fputc here */
/* e.g. write a character to the UART3 and Loop until the end of transmission */
HAL_UART_Transmit(uartHandlerDebug, (uint8_t *)&ch, 1, HAL_MAX_DELAY);
return ch;
}
/* USER CODE END 4 */
}I have only put the relevant functions in the code snippet above.
However, when I switched the value of uartHandlerDebug to huart2, and I rerun the code, nothing is printed on my PuTTY terminal.
This is my pin configuration:
My UART2_RX pin is PA3, TX pin is PA2
My UART3_RX pin is PD8, TX pin is PD9
This is my PuTTY terminal configuration, although I don't think that should be the factor here:
I will greatly appreciate any help. Thank you!
Edit 1: I am using STM32 NUCLEO-F746ZG. The board is connected to my PC via a simple Micro USB cable.
Edited to apply source code formatting - please see How to insert source code for future reference.
1 ACCEPTED SOLUTION
Accepted Solutions
Hello,
If you are using NUCLEO-F746ZG board, that's normal. USART3 is connected to STLINK-VCP (Virtual ComPort), while USART2 NOT.
From the bord schematic:
If you need to use USART2, you need to connect USART2_Tx and USART2_Rx to respectively to STLINK_Rx and STLINK_Tx over CN5:
But you need to keep USART3_Tx and USART3_Rx pin not initialized (Hi-Z).
@is45 wrote:not very sure whether my board has VCP, !
The User Manual is the place to check that:
via: https://www.st.com/en/evaluation-tools/nucleo-f746zg.html#documentation
