A modular TCP/IP stack for embedded systems with a tinyTimber interface

Many of today’s embedded systems require internet connectivity for monitoring and control. Most of these systems use a stack implemented on specific hardware. This requires a lot of hardware specific software and might make it too time-consuming to exchange or upgrade the communication hardware. Using a standardized communication protocol such as the Point-To- Point-Protocol (PPP) makes it easier to exchange the hardware but also requires a software stack with support for PPP. EISLAB has been trying to find a viable solution for this problem but have been unable to do so. This project aims to provide a lightweight, modular and hardware independent software stack for end hosts with support for PPP. Additionally it should support a tinyTimber interface to facilitate real-time applications. The current stack implementation is portable enough to run on anything ranging from a regular home-PC to a PIC18 8-bit microcontroller. It should be trivial to port it to any architecture in that range. The memory requirements of the stack are low enough to run on the PIC18F6622 and still have most of the memory(> 70%) available to the application. While we initially planned to run the stack using tinyTimber on the PIC18 , we came to the conclusion that the limitations imposed by the architecture where too strict. This decision was made after porting tinyTimber to the PIC18. Since there is a tinyTimber interface for the stack it is quite possible to run the stack using tinyTimber on the PIC18. This however, is not recommended since it would consume most of the system resources. It’s worth noting that while the PIC18 is not a suitable architecture to run multithreaded tinyTimber there are other architectures that are more suited for this task, such as the ARM, that might use the tinyTimber interface to the stack. To be able to test the tinyTimber interface we also had to developed a version of tinyTimber that is capable of running on any POSIX compliant system.Validerat; 20101217 (root