The design of the cascaded network interface based on DM9003 and STM32

In order to cascade the Ethernet interface, reduce the equipment cost and simplify the interface circuit during data transmission between multiple network interfaces, this design used STM32F103RBT as the key control unit, we can cascade the network interface by driving the dual-port network card chip DM9003EP. We used STM32 microcontroller to initial the network card chip and control data communication. In order to cascade the network data interface, we used port 0 of the DM9003 chip to receive the data from PC, and port 1 as the data sending port of the next level. Paired with the use of TCP/IP protocol stack and UIP protocol stack, we realized the receiving and sending of the TCP and UDP packets between multiple network interfaces.