printf重定向 在gcc和keil都可以使用

#ifdef __GNUC__
  #define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
  PUTCHAR_PROTOTYPE
  {

  HAL_UART_Transmit(&huart1, (uint8_t*)&ch, 1, HAL_MAX_DELAY);

  return ch;
  }
  int _write(int file, char *ptr, int len)
  {

      int DataIdx;

      for (DataIdx = 0; DataIdx < len;DataIdx++)

     {

           __io_putchar(*ptr++);

     }

      return len;

  }
  
  #else
  #define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
  PUTCHAR_PROTOTYPE
  {
		HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);
		return ch;

  }
  #endif