双口RAM，实现数据的缓冲，能够使数据有序收发，实现数据的交互，同时，可以作为大容量ram使用，把需要的数据有序存起来以备其他使用-Data buffer, to enable orderly send and receive data, interaction data, while the ram can be used as a high-capacity, the need for orderly storage of data to use it for other，Data buff