Modbus 80C166

Hi Patrick, Have a look at

The web site contains the specification as well as links to some code snippets. Modbus is a fairly simple protocol. It's the environment around it that needs a bit more work in order to be easily integrated with the rest of the system. Some form of database abstraction is useful to have (since basically all modbus messages reads and writes to specific addresses in a "database"). An SQL database would of course be overkill (especially in a resource-constraint embedded system) but something simpler will make the work much easier. There are also a TCP version of the protocol, that basically encapsulate the modbus messages in a TCP data stream. Very simple and easy to implement!

If you are interested in a commercial solution, our company have a working program package that implements the protocol. It has been used in a custom project, in an industrial application.

I hope the link above is of any use! Regards, //Anders Rosvall