Optimizing Embedded Product Design The Case for Off-the-shelf Boards

15.02.2024 Nathan Collins No comments

Choosing the right system-on-chip (SoC) is probably your first consideration when designing an embedded product, followed closely by deciding whether to use an off-the-shelf board or design your own.

The case for commercial boards in initial designs

For the first product in a new line, consider using a commercially available board that features your chosen SoC. This approach may slightly increase the cost per board compared to building a custom board yourself. However, it lets you build on a vendor’s considerable expertise in areas like SoC characteristics, architectural layout, proper bus design, and errata workarounds. Pre-existing boards offer a significant shortcut in getting your product to market as they can minimize prototype iterations and reduce the risk of crucial mistakes in layout. As you gain experience with your chosen silicon and start looking at moving to higher-volume production, you can then consider whether it makes sense to design and manufacture custom boards to reduce costs and introduce custom functionality.

First step: Picking a vendor

Selecting a CPU architecture is your very first step. While ARM is currently dominating the market, Intel x86 and RISC-V are other possible alternatives. Because toolchains like LLVM and GCC can support all these architectures, your decision will usually depend on factors such as vendor and community support, licensing, power consumption, and clock speeds. Once you’ve selected an architecture, comparing features and prices within that family becomes more straightforward.

Evaluating silicon vendor boards

Silicon vendors such as AMD, Intel, Nvidia, NXP, and Renesas all offer eval boards to help you evaluate their SoCs. These boards are excellent starting points but there are things to consider.

• Feature overload. Because eval boards are intended to show off the capabilities of their chips, they are often loaded with features. That can be good for trial, but you don’t want to pay for unnecessary hardware once you move to volume production.
• Limited availability. Eval boards are often intended for very limited distribution, making availability a serious concern. If you’re planning on a very small production run, this might not matter. But it also might force you to move to another platform before you’re ready.
• Hardware consistency. Eval boards may not have the same process consistency as commercial products. That means you could get multiple hardware revs of the same board within a short timeframe, creating potential software compatibility nightmares and in-field surprises.
• Support limitations. Support (either engineering assistance or device drivers) may not be at the level you need to build product. That includes some critical aspects such as OS updates. It’s possible the vendor has the capacity or process for consistently delivering commercial quality drivers for their boards that are compatible with the latest Linux releases, but you’ll likely need to ask.

It’s always advisable to consult with a sales representative before using an eval board in a production product. Their feedback can prevent future issues and, if necessary, direct you to distributors for better long-term alternatives.

Choosing a board provider

The other option for using pre-made boards is to go to a board vendor instead of a silicon vendor. They’re creating boards with the intent they’ll be incorporated into products rather than simply for evaluation. When selecting a board provider, consider all aspects, including one of the most important peripherals, the screen. For a more comprehensive guide on selecting hardware, refer to our paper on best practices: Designing Your First Embedded Linux Device: Choosing Your Hardware.