说明：  rt8019as网卡芯片的驱动，我自己写的，与网上所能下载到的同类代码最大的区别是，我这个驱动可以使网卡工作在很繁忙的网络环境中，即使cpu使用的是单片机，也不会使网卡fifo溢出而使网卡不能通信
(rt8019as chip card driver, I wrote it myself, and on-line can be downloaded to a similar code biggest difference is that my network card driver can work in a very busy network environment, even if the cpu is a single-chip microcomputer use, but also not fifo overflows of LAN card can not be communication)