Not able to print log on putty terminal

[Mehulrana511]

Hello,

I am working with the STM32H7S78-DK board, and I have enabled the UART4 serial interface (using PD0/PD1) for both programming and debugging. However, I am unable to print logs to the Putty terminal.

Environment:

• STM32H7S78-DK Board
• UART4 on PD0/PD1
• Putty Terminal 
• STM32CubeIDE and HAL Library for configuration

I have set following parameters ,
• 115200 bps
• 8-bit data
• No parity
• One-stop bit
• No flow control

Here is my code

/* USER CODE BEGIN Header */
/**
  ******************************************************************************
  * @file           : main.c
  * @brief          : Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2024 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stdio.h"

/* USER CODE BEGIN PV */

/* USER CODE END PV */

/* Private function prototypes -----------------------------------------------*/
static void MX_GPIO_Init(void);
static void MX_UART4_Init(void);
/* USER CODE BEGIN PFP */
#if defined(__ICCARM__)
/* New definition from EWARM V9, compatible with EWARM8 */
int iar_fputc(int ch);
#define PUTCHAR_PROTOTYPE int iar_fputc(int ch)
#elif defined ( __CC_ARM ) || defined(__ARMCC_VERSION)
/* ARM Compiler 5/6*/
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#elif defined(__GNUC__)
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#endif /* __ICCARM__ */
/* USER CODE END PFP */

/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */

/* USER CODE END 0 */
/* USER CODE BEGIN PFP */

/**
  * @brief  The application entry point.
  * @retval int
  */
int main(void)
{

  /* USER CODE BEGIN 1 */

  /* USER CODE END 1 */

  /* MCU Configuration--------------------------------------------------------*/

  /* Update SystemCoreClock variable according to RCC registers values. */

  SystemCoreClockUpdate();

  /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
  HAL_Init();

  /* USER CODE BEGIN Init */

  /* USER CODE END Init */

  /* USER CODE BEGIN SysInit */

  /* USER CODE END SysInit */

  /* Initialize all configured peripherals */
  MX_GPIO_Init();

  MX_UART4_Init();
  /* USER CODE BEGIN 2 */


  /* Output a message on Hyperterminal using printf function */
  printf("\n\r UART Printf Example: retarget the C library printf function to the UART\n\r");
  printf("** Test Start successfully. ** \n\r");


  /* USER CODE END 2 */

  /* Infinite loop */
  /* USER CODE BEGIN WHILE */
  while (1)
  {
    /* USER CODE END WHILE */
	  printf("Hello from STM32H7S78-DK!\n\r");
	  HAL_Delay(1000); // 1-second delay
    /* USER CODE BEGIN 3 */
  }
  /* USER CODE END 3 */
}


/**
  * @brief UART4 Initialization Function
  * @PAram None
  * @retval None
  */
static void MX_UART4_Init(void)
{

  /* USER CODE BEGIN UART4_Init 0 */

  /* USER CODE END UART4_Init 0 */

  /* USER CODE BEGIN UART4_Init 1 */

  /* USER CODE END UART4_Init 1 */
  huart4.Instance = UART4;
  huart4.Init.BaudRate = 115200;
  huart4.Init.WordLength = UART_WORDLENGTH_8B;
  huart4.Init.StopBits = UART_STOPBITS_1;
  huart4.Init.Parity = UART_PARITY_NONE;
  huart4.Init.Mode = UART_MODE_TX_RX;
  huart4.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart4.Init.OverSampling = UART_OVERSAMPLING_16;
  huart4.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
  huart4.Init.ClockPrescaler = UART_PRESCALER_DIV1;
  huart4.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
  if (HAL_UART_Init(&huart4) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetTxFifoThreshold(&huart4, UART_TXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_SetRxFifoThreshold(&huart4, UART_RXFIFO_THRESHOLD_1_8) != HAL_OK)
  {
    Error_Handler();
  }
  if (HAL_UARTEx_DisableFifoMode(&huart4) != HAL_OK)
  {
    Error_Handler();
  }
  /* USER CODE BEGIN UART4_Init 2 */

  /* USER CODE END UART4_Init 2 */

}


/* USER CODE BEGIN 4 */

/* USER CODE END 4 */
/**
  * @brief  Retargets the C library __write function to the IAR function iar_fputc.
  * @PAram  file: file descriptor.
  * @PAram  ptr: pointer to the buffer where the data is stored.
  * @PAram  len: length of the data to write in bytes.
  * @retval length of the written data in bytes.
  */
#if defined(__ICCARM__)
size_t __write(int file, unsigned char const *ptr, size_t len)
{
  size_t idx;
  unsigned char const *pdata = ptr;

  for (idx = 0; idx < len; idx++)
  {
    iar_fputc((int)*pdata);
    pdata++;
  }
  return len;
}
#endif /* __ICCARM__ */

/**
  * @brief  Retargets the C library printf function to the USART.
  */
PUTCHAR_PROTOTYPE
{
  /* Place your implementation of fputc here */
  /* e.g. write a character to the LPUART1 and Loop until the end of transmission */
  HAL_UART_Transmit(&huart4, (uint8_t *)&ch, 1, 0xFFFF);

  return ch;
}

/**
  * @brief  This function is executed in case of error occurrence.
  * @retval None
  */
void Error_Handler(void)
{
  /* USER CODE BEGIN Error_Handler_Debug */
  /* User can add his own implementation to report the HAL error return state */
  __disable_irq();
  while (1)
  {
  }
  /* USER CODE END Error_Handler_Debug */
}

#ifdef  USE_FULL_ASSERT
/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @PAram  file: pointer to the source file name
  * @PAram  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* USER CODE BEGIN 6 */
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
  /* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

Any guidance or troubleshooting tips would be greatly appreciated.

Thank you for your support.

Best regards,
Mehul 

[SofLit]

Hello,

Did you try first sending chars by just using HAL_UART_Transmit() ?:

Example:

HAL_UART_Transmit(&huart4, (uint8_t *)"Test", 4, 0xFFFF);

You need to validate that part first before going ahead to the redirection of printf.

And what is the IDE you are using? IAR?