Development boards are printed circuit boards containing processor with necessary supporting elements. Typically such board contains only few (or none at all) external devices. Instead, processor lines are exposed via connectors attached to the board. This allows connecting external modules containing needed devices.

Minimally development boards allow loading of program to the processor and running it. Most boards contain additional debugging support allowing breakpoints, single stepping and checking memory content. Usually it is also possible to interact with devices integrated into the same chip. Among board that we will use Arduino do not have debugging interface (debugging support is limited to printouts via serial port).

Some more complicated development boards contain extra devices. This simplifies writing programs which use them. Extra devices like displays can help with debugging. However, extra device limit flexibility of development board and increase cost. Therefore boards that we will use are simple and most contain almost no extra devices.