Selecting 8-bit MCUs: A practical guide

Steve Terry, SK Communications (and advisor to Component Engineering Consultants)
EDN, October 28, 2011

Many devices may be available that will do the job, but tailoring the selection tightly to your particular needs can make for a much smoother ride in the long run.

Many small board designs benefit nicely from the use of a microcontroller. But selecting an appropriate one for a particular design often brings on the feeling of "Where do I begin?"

This discussion limits its focus to low-end microcontrollers. For this purpose, we'll stick with 8-bit devices. 8 bits simply means that internal processing only operates on 8 bits at a time. As one would expect, 16- and 32-bit micros would operate much faster as they are processing more bits of data with each instruction.

To be sure, much of the same thinking applied to 8-bit microcontrollers can be applied to 16- and 32-bit devices; however, cost, size, capabilities, performance, feature integration, and a host of other upscaled attributes quickly make it increasingly difficult to generalize on approach and applicability.

That said, even in the 8-bit microcontroller world, there are many highly specialized devices. So, to avoid confusion, we'll leave that subject for a future discussion and stay with the garden variety parts for now. Quite often, if your design truly calls for one of these specialized micros, there's not going to be much choice, and you'll likely be familiar with those choices already, so you should be okay.

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