Embedded systems programmers sometimes face the problem of in-house-designed hardware that cannot be integrated with one of the standard toolkits available in a graphics environment.

The principles involved in controlling such a system are the same whether it has a windowed graphics display controlled by a mouse and keyboard combination, or an interface as basic as a digital watch’s. This paper provides broad guidelines for the organization of a user interface that can be applied to any sort of external input, providing a starting point from which to grow a design that fits your particular requirements.