yl公司板子添加串口的方法 他们不给技术支持的 因为他们的BSP介于4.2和5.0之间 所以网上的很多方法也不对 这个是好使的 我摸索出来的-yl company board serial method to add them to the technical support of the BSP because they ranged from between 4.2 and 5.0 so the Internet is not responsible for the many ways th