Question of the Month: What is the most important element when choosing a microcontroller to be used in a project?

There are many factors that influence your selection.

Most important are requirements and cost of the development capability.

Back when I was doing embedded systems, the cost of the development system often drove the selection, though not always.

The company wanted to standardize on one processor family, but we kept pointing out that the one they wanted to use would not meet the customers requirements.

michaelkellett said:

Over the last 2 years the primary issue has been availability - so many parts are unobtainable.

I found this is where the use of the Arduino IDE, and similarly with MbedOS (+ few others), has added value, especially during prototyping phase, as in most cases you do not have to change your code base to use a different Arduino compatible MCU if the one you started with is no longer available.

This is also where C++ classes help too if developing your own library.

Then, thanks to the ease of KiCAD and EasyEDA, I spend a bit more time coming up with different designs based on these different MCU's.

Being adaptable is the name of the game now.

For our most recent project, conceived in the middle of a chip shortage - it was availability that was the primary element. If you can't buy it, especially for a project to be developed within a month or two ... then it's pointless.

But in other times, I'd say features/cost matching needs is important. Other times, especially for RF, availability in a module with antenna that is pre-qualified can be a major sway.

- Gough

Is a recent hobbyist I prefer to use the Python programming language. I don't like flavored versions of Python that tie you to a specific IDE or even frameworks that also tie you to specific hardware. Unfortunately, opensource MicroPython can lack support for specific hardware or peripherals. If I was working on more complex projects the C language would be better suited but not for my hobbyist interests.

Availability and what you have in the cupboard definitely can dominate the decision.

Depends heavily on the project requirements.

Some other important elements not on the above criteria list might be the quality and availability of supporting documentation, training materials, application notes, code libraries, and also if we are talking board level devices here, then board form factor and power consumption.

As others have said, the first level requirement is that its capabilities match the application.

However, most times, there are going to be multiple options, so that is rarely the limiting criteria.

That said, cost is probably going to be the next level consideration. And that cost has to include development time. In some cases, going with a micro that you know better but has a higher per-part cost might make more sense than just pushing the BOM to the bottom. (On the other hand, on a very high volume project, the additional dev time it takes to learn a new platform might be worth it.)

It just has to be "other".

Requirements can include things like architecture, dev tool experience/ownership etc.

For some jobs the price of the device is significant  but for others (eg custom test equipment which I do quite a bit of) then it hardly matters at all. The development cost may run into tens of £k and three boards are built (one for me, one for the application and one spare). The cost of the processor just doesn't feature.

Over the last 2 years the primary issue has been availability - so many parts are unobtainable.

MK

Voted Other - 100% agree with dougw - features need to match requirements. I chose Raspberry Pi Pico in one project over Arduino Nano since qty 2 i2c ports were needed. If a project needs BLE or Wifi, the microcontroller needs that feature. 

Least effort to implement is pretty significant as well.

IMHO, cost of the overall project to build is more impact than just the cost of a microcontroller. 

#2 Choice:  Familiarity with the IDE is becoming more of an influencing factor.  When the learning curve is more like scaling the Dawn Wall... it's just no fun.  I move on to different things.