在IAR中实现printf

在IAR中实现printf需要重写__write()

size_t __write(int handle, const unsigned char * buffer, size_t size)
{
  /* Sending in normal mode */
  if(HAL_OK == HAL_UART_Transmit(&huart3,(uint8_t *)buffer,size,0xff))
   {
      return size;
  }
  else
  {
    return -1;
  }
}

按照个人配置只需要修改huart3即可。