Choosing between an SBC and a core module is a trade-off between time to market and flexibility. A single board computer is a ready to go instant platform that ships with all the drivers needed in the form of a board support package (BSP). A core module (also known as a computer-on-module (COM) or system on module (SOM)) is half-way between an SBC and a discrete microprocessor IC. It offers more flexibility than an SBC, without the much higher development effort associated with a discrete solution.
Clearly an SBC saves a lot of integration effort and development time. It comes out of the box as a fully working solution that just needs to be loaded with the application software and interfaced to the display. The issues we run into most often are size and I/O. Each manufacturer offers a limited range of SBC options with different and fixed permutations of I/Os, size and features. So, it is a matter of selecting the most suitable option from the range – you can’t customise the board in accordance with the needs of the application.
The advantage of the core module path is that you can design the carrier board exactly according to your size and configuration requirements, and then connect an SoM to it. Clearly this will take time and design effort, but will allow you to create a board with exactly the I/O that you need for your design and of the right form-factor.
There is also a third potential avenue. Some suppliers like AndersDX with its DX range has developed its own range of baseboards with interchangeable core modules. You can start your development on these platforms, work on the software and in the meantime, develop your own baseboard if you choose to.
What are the key considerations in choosing a single board computer or core module?
The decision to choose an SBC or a COM depends on the specific project requirements and sales volume. Whichever route you opt for, the most important specifications are:
- The interfaces provided for sensors and actuators
- How many are there, and are they the right ones
- The connectivity options for the network and Internet.
- Support – which can make a big difference to how long it takes to get your project up and running:
- Is there a well-supported and robust board support package – how much other help is available for the software developer?
Other things matter too:
- Temperature range – will it work in hot/cold conditions?
- Longevity of supply – will you still be able to get it in ten years’ time?
- Power – especially if it needs to run from a solar panel or battery
Last by no means least is the cost. If a board is to be sent out into the field in any volume, budget is always going to be a factor.
Having drawn up a shortlist of boards that tick the technical boxes, it is well worth taking a hard look at the organisation you’re sourcing the board from. A good supplier with a partnership mentality can make a huge difference to your time to market.
Essentially processor choice boils down to balancing three key factors:
- Processor performance and specifications
- Format: SBC or COM (not all processors are available in both of course)
- Supplier and the support that they offer.
All three need to be right and working in harmony with each other. Selecting the optimal processor but working with a supplier who isn’t willing or able to help you with the design issues you’ll encounter on your journey can significantly lengthen your time to market and even put the success of the project in jeopardy.