uart_printf.c

/* 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__ */

/**
  * @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 USART3 and Loop until the end of transmission */
  HAL_UART_Transmit(&huart3, (uint8_t *)&ch, 1, 0xFFFF);

  return ch;
}