Designing low cost embedded systems with ethernet connectivity

This paper focuses on hardware and software aspects in development of low cost embedded systems with Ethernet interface for industrial applications like smart sensors and mechatronic control. Ethernet connectivity allows a standard and easy networking method as well as remote Internet access but usually requires higher resources (processing power and memory) than serial connections like RS232/485. Embedded systems based on low cost 16 bit microcontrollers have limited resources so Ethernet access implementation requires careful hardware and software design. Our paper presents a simple solution for implementation of Internet access for simple industrial control systems and smart sensors. Hardware is based on low cost Ethernet controller chips attached to 16 bit low power microcontroller with limited memory resources (0.5...4Kbytes RAM) and software is a simplified, low memory footprint TCP/IP stack implementation that offers Ethernet connectivity in local network. For Internet access, a standard router with enabled VPN (Virtual Private Network) can be attached to local network. Some performance tests and analysis regarding communication speed, RAM memory requirements for microcontroller are presented.