Unveiling the Power and Flexibility of Computer-on-Module Standards: A Comprehensive Overview

In the ever-evolving landscape of embedded computing, leveraging Computer-on-Module (COM) standards is critical to facilitate scalability, interoperability, and design flexibility. Among the prominent standards are ETX, XTX, Qseven, SMARC module, COM Express, and the latest addition, COM-HPC. This article delves into the world of COM standards, unraveling their advantages and exploring how they revolutionize the embedded systems industry. 

I’m a strong believer in open standards. An old, but still true statement to support my opinion is “don’t reinvent the wheel”. The result of a translation this fact to the world of embedded computing are open standards for computer modules. 

I’m an electronics engineer working in marketing for many years. One traditional marketing thinking is “What’s unique with my product?”. After intense discussions internally – back in the year 1999 – the decision at a medium sized embedded computer company Jumptec was: Our Computer-On-Module must be interchangeable with products from 3rd party vendors. This will create a new market segment. Today, 25 year later I have to admit that this was exactly the right decision. The worldwide market for Computer-On-Modules already passed the 1 billion dollar mark annually – and it continues to grow fast. 

ETX (Embedded Technology eXtended)

ETX, is one of the earliest COM standards. It defines a compact form factor with standardized dimensions, connectors, and pinouts, allowing for easy interchangeability. ETX modules encapsulate the core components of a computer, including the processor, memory, and essential I/O interfaces. The modular approach enables seamless upgrades, simplifies maintenance, and accelerates time-to-market for embedded solutions. In fact, ETX was the first open standard Computer-On-Module definition. Jumptec initiated the first specification which was hosted by an industry consortium later. Jumptec, Advantech, I-Base, IBR and PCI-Systems have been the first companies providing ETX modules. There have been some others like UTX or STX defined the same time, but all of these have been proprietary. ETX was defined 25 years ago – but it’s still in use and some modules are still available on the markets. The old carrier board designs can still be used with much newer modules – a clear proof the COMs enhance the longevity of embedded designs. 

XTX (eXtended Technology eXtended)

The main extension interface for ETX was the outdated ISA bus (defined in the early 80s by IBM) which was replaced by the much faster PCI Express lanes and SATA interfaces. XTX in fact is just an  extension of the ETX specification. With XTX it’s possible to upgrade to much higher IO and data storage performance with a minimum redesign work on the carrier board. 

The XTX definition was the first activity of the new startup company congatec in 2005. Most module vendors which offered ETX modules upgraded their product portfolio to XTX. 

Qseven

In 2008 the CPUs became less energy hungry and the demand for a smaller open standard was visible. Together with Seco, later also with MSC, congatec started to define a compact 7x7cm sized module based on the rugged, but very cost efficient MXM2 connector. The specification was hosted by an industry consortium. As the transfer of the specification to PICMG failed – mainly because of pollical issues – a new consortium was founded in March 2012 – SGET was born and was voted to be board member. Since 2012 I’m on the board of the SGET holding changing positions, treasurer, vice-chairman and also president.  

SMARC Module

Short for Smart Mobility ARChitecture, Smarc modules prioritize mobility, making them ideal for applications in portable and power-sensitive devices. Smarc defines a small footprint with low power consumption, making it suitable for battery-powered and energy-efficient embedded systems. With standardized connectors and interfaces, Smarc modules enhance design flexibility while keeping compatibility. 

SMARC started as ULP-COM, a module standard for ARM processors supported by two vendors only. It’s major success started with the transfer of the specification to SGET and the release of rev. 2.0. In my role as specification editor, I was able to set up a forward thinking to the workgroup which resulted in a highly successful specification. 

COM Express

By today, COM Express is the most successful open standard COM definition. The first release of the COM Express specification was published in 2005. Since then, two major updates happened. The Rev. 2.x added the new type 6 pinout and the mini size with type 10 pinout. With Rev. 3.x the server pinout type (Type 7) was defined to address headless high performance server applications too. 

Since Rev 2.0, release Aug 2010, I was editor for all specification document. This does not only include the hardware specification Rev. 2.0, 2.1, 3.0 & 3.1 but also includes the EEPROM, the Embedded API and the Carrier Board Design Guide documents. My belief in open standards made me investing a lot of my energy into this specification. I’m proud to be one of the makers behind this great international success. 

COM-HPC

COM-HPC is the designated successor of COM Express. As chip technology moves fast – also the Computer-On-Module definitions have to follow this trend. Main driver behind COM-HPC is performance. In computing performance but also in IO performance. 

For this standard I was involved from the very beginning. Starting with first congatec internal brainstorming, first discussions with Adlink and Kontron at the Embedded World in Nürnberg in 2018 and being voted as chairman for the PICMG workgroup in October 2018. Since then, there are weekly conference calls, in peak times we even established two parallel working sub-groups, one for the complete signal integrity part, the other for the platform management part. The COM-HPC specification is not just a single document. 

• Hardware Specification Rev. 1.2 (237 pages)
• Preview Specification Rev. 1.2 (50 pages)
• Embedded API Rev. 1.0 (~ 50 pages)
• Carrier Board Design Guide Rev. 2.2 (163 pages)
• Platform Management Interface Specification (94 pages)
• Embedded EEPROM specification for COM-HPC Rev. 1.0 (139 pages)

This is more than 700 pages of documentation, but don’t worry, most of this is only relevant for companies to design modules. The Carrier Board Design Guide is the most important document to be referenced if you plan to make your own carrier board. 

COM-HPC is a forward looking standard was defined in a forward looking way and it’s very well documented. As chairman of the workgroup and co-editor for some of the documents I’m proud about the results. All of the personal investments of all workgroup members enabled this. And we already see that COM-HPC launched successfully. It’s a further big step to make it unnecessary to “reinvent the wheel”. 

Advantages of COM Standards:

Conclusion

In the dynamic world of embedded computing, the use of Computer-on-Module standards has become indispensable. From the foundational ETX and XTX to the power-efficient Qseven, Smarc, and versatile COM Express, and the cutting-edge COM-HPC, these standards offer a spectrum of options to meet the diverse needs of the industry. The advantages of scalability, interoperability, reduced time-to-market, future-proofing, and cost efficiency position COM standards as a driving force in the evolution of embedded systems, ushering in a new era of innovation and possibilities.