STM32 CubeMX ST-LinkV2.1 : how to redirect printf

[David PICARD]

Posted on February 02, 2017 at 09:31

I found several posts like

http://www.openstm32.org/forumthread339

, using syscalls.c, but I don't have this file in my project... I generate the code with CubeMX v4.18.0.#qt-creator #cubemx #stm32 #arm-none-eabi

[Sirma Siang]

Posted on February 02, 2017 at 09:47

Hello David,

To get printf working, you have to do the following.

In the main.c, add this code in the relevant sections:

• /* USER CODE BEGIN Includes */

  #include

  'stdio.h'

  /* USER CODE END Includes */

• /* USER CODE BEGIN PFP */

  /* Private function prototypes -----------------------------------------------*/

  #ifdef

  __GNUC__

  /* With GCC/RAISONANCE, small

  printf

  (option LD Linker->Libraries->Small

  printf

  set to 'Yes') calls __io_putchar() */

  #define

  PUTCHAR_PROTOTYPE

  int

  __io_putchar(

  int

  ch)

  #else

  #define

  PUTCHAR_PROTOTYPE

  int

  fputc(

  int

  ch, FILE *f)

  #endif

  /* __GNUC__ */

  /* USER CODE END PFP */

• /* USER CODE BEGIN 4 */

  /**

  * @brief

  Retargets

  the C library

  printf

  function to the USART.

  * @

  param

  None

  * @

  retval

  None

  */

  PUTCHAR_PROTOTYPE

  {

  /* Place your implementation of

  fputc

  here */

  /* e.g. write a character to the EVAL_COM1 and Loop until the end of transmission */

  // HAL_UART_Transmit(&UartHandle, (uint8_t *)

  &ch

  , 1, 0xFFFF);

  HAL_UART_Transmit(&huart2, (

  uint8_t

  *)&ch, 1, 0xFFFF);

  　

  return

  ch;

  }

  /* USER CODE END 4 */

In combination with the syscall.c, you should get your printf getting out on the UART.

Kind regards

Sirma

[Sirma Siang]

Posted on February 02, 2017 at 09:50

Addapt the code to the uart handler you are using 🙂

With cube, I generate mine with UART2. So in the code huart2 has been used.

You can refer to some projects examples in the firmware library directory.

Under the family you are using, you will find them.

Kind regards

Sirma