说明：  以太网编程，PHY芯片DM9000的电路图和PCB封装及外围电路图，以及PCB制版。自己自作成功，很好用。
(The DM9000 is a fully integrated and cost-effective, single chip fast Ethernet MAC controller. It has a general interface, an adaptive 10\/100M PHY and 4K DWORD SRAM.)