.TCP / IP Protocol Stack, Customization And Implementation Of Embedded Systems

With the embedded system and network getting popular, the way of accessing to network changes gradually. More and more equipment with embedded TCP/IP protocol stack can access the Ethernet network directly even without the PC or main frame computer. Recently sharing information through Ethernet for the embedded equipment with microprocessor becomes a hot issue in the world of electronics. Generally speaking, a built-in TCP/IP protocol stack is needed for a embedded system to access the internet in order to realize reliable communication. Because the embedded system only has limited resources and low power cosumption requirement, trade-offs must be made between the functions and resources. For most cases of sensor nodes, the complicated functions of the full TCP/IP protocol stack are not used. So it is very important to get an abbreviated or concise version of full TCP/IP protocol for the embedded system with 8 bit microprocessor, according to the special demand of the system communication. This paper will focus on the concise version of TCP/IP protocol stack customized in 8 bit microprocessor.The proposed system with embedded TCP/IP protocol stack can work as a embedded server, local or remote client can access the data resource of the server through a Hub to realize data exchange. For our system based on 8 bit microprocessor PIC18F67J60 with 10 bit A/D convertor, a set of TCP/IP protocol stack which fit the embedded system is customized according to the requirement, including ARP protocol,IP protocol,ICMP protocol,UDP protocol,TCP protocol,DHCP protocol and so on. These protocols are modified and realized selectively. The optimized protocol stack can save a lot of system resource. A 10Base-T ENC28J60 Ethernet interface chip of Microchip Technology is used to connecte the Ethernet. The embedded system can be visited and controlled after it is connected to the Ethernet. So sound signals of the monitoring nodes can be accessed and monitored easily from the remote terminal. Our optimized protocol stack is implemented, tested and verifed in 8 bit microprocessor PIC18F67J60. The embedded system runs successfully and realizes the low cost access to the Ethernet.