Abstract: This paper describes the implementation method and technology of ethernet interface card based on USB BUS.A 10BASE-T ethernet adapter based on USB1.1 protocol has been designed.The hardwares of the system mainly comprise S3C44B0X (MCU,Samsung company),PDIUSBD12 (USB control chip) and  CS8900A ethernet interface chip).The firmware was developed in ADT1000 integrated development environments provided by CVTech company,coded in Assemble and ANSI C language.

Key words: USB, S3C44B0X；ethernet；hardware structure；firmware