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Overview and List of System-on-Module and Computer-on-Module Standards – Q7, SMARC, EDM, and More

A System-on-Module (SoM), also known as a Computer-on-Module (CoM), is a small board with the key components of a computer such as SoC, memory, and possibly others components such as PMIC (Power Managment IC), and Ethernet PHY, as well as one or more connectors used to connected to a baseboard, also called carrier board, which features standard ports such as Ethernet (RJ45), USB ports, SATA, power jack and so on. The advantages of using of baseboard + SoM design compared to a single board are at least two fold:

  1. Most of the PCB design complexity is often around the CPU/SoC and high speed buses connected to the CPU/SoC. So you could buy a SoM, design your own baseboard and get a complete design relatively in a short amount of time, with reduced development resources and costs.
  2. The design is modular, so you could easily upgrade from one SoM to another one. For example, in order to provide a product with several option, you could use one baseboard with 3 SoMs featuring single, dual and quad core processors.
Qseven (Right) and SMARC (Left) Systems-on-Module – Roughly to scale

This all looks very nice, but many SoM solutions are proprietary often based on a 204-pin SO-DIMM connector, and in that case, albeit you may still have a wide range of different SoMs, you’d be stuck with the same vendor, unless you also change your baseboard design. To work around this problem, companies are started to launch SoM standards in order to be able to mix SoMs and baseboards from different vendors. The only problem is that in recent years, different companies have tried to launch their own standard, which in some cases appear to be only used by the company. Exception are SMARC and QSeven where I’ve seen ARM and x86 SoMs from several companies, and older x86 only standards such as COM Express and PC/104. AFAIK, All 4 standards are targeting industrial embedded applications, and not so much the consumer market.

So I’d like to list a non-exhaustive list of SoM / CoM standards, and possibly start a discussion as to why there needs to be so many standards, and companies do not come together behind a handful of standards instead. I’ll focus mostly on low power SoMs, but I’ll also mention “conventional” x86 only standards at the end of the list.

The list is not complete, and there are other standards, mainly, or only, used within the company that defined them, such as Phytec PhyFlex, and SolidRun μSOM found in Cubox-i and Hummingboard.

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