A Perfect Couple - Qseven and PC/104

Adopting Qseven technology will lower costs, speed development, and aid scalability

By Franz Fischer, congatec Inc.

A recent innovation in computer-on-module (COM) technology has been the introduction of the ultra-compact Qseven form factor. Measuring only 70mm x 70mm, it uses an MXM system connector with a standardized pin-out regardless of vendor. (See Figure 1.)

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The Qseven form factor was defined as an open standard, primarily aimed at ultra-low-power applications. Open standards allow any company to build, market and sell their own Qseven products to end customers; it’s fundamental to any product that will be used by the industry. Open standards ensure that customers have a second-source supplier, which is one of the key goals of the COM concept.

Just like COM Express, ETX and XTX, Qseven provides a scalable platform with a range of processor options, as well as customizable BIOS with custom flat-panel support within the BIOS.

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The best of both worlds
Compared to the PC/104 form factor, which measures 90mm x 96mm, the Qseven module is a complete PC-on-module in a much more compact format. However, an ideal scenario might be to have PC/104 support for Qseven technology by way of a PC/104 custom carrier board. (See Figure 2.) This would provide all of the COM benefits to PC/104 designers, providing scalable products using a wide range of Intel® Atom™ processors on the same carrier design with customizable BIOS. The defined open-standards Qseven pin-out specification would allow PC/104 venders to offer products from different Qseven suppliers with the same carrier design.

Recently a new Qseven PC/104 carrier card has become available that meets the specifications and price points of PCI/104-Express. (See Figure 3.) This makes Qseven COM technology accessible to many PC/104 form-factor system developers, providing all the benefits of COMs. There are a wide range of Qseven modules available with older Intel Atom processors through to the latest Intel® Atom™ processor E6xx series. With Intel’s guaranteed support for the processor range of typically seven years from processor launch, this provides real choice to system builders and allows long-term product management for existing and future PC/104 projects. Additionally, new ranges of processor shall be made available that will be pin-compatible with Qseven specifications, allowing much easier mid-life equipment updates.

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The latest Intel Atom processor E6xx will be available shortly in extended temperature ranges, featuring -40 degrees C to +85 degrees C operating temperatures for truly embedded applications.

COM technology has been shown to improve time to market for new and existing designs, at the same time reducing complexity of design for the system builder as the Qseven supplier takes ownership of the complexities of the Qseven module design. System designers have the choice to make their products scalable by using different COM product options, directly based on power, performance and cost. COM is pin-compatible, reducing legacy nightmares of the past and allowing smoother mid-life updates. With adoption of the new and open Qseven standard starting to build up very quickly, new product developments will be guaranteed near legacy-free upgrades for the future.

Technical details of the integration
COM products are nearly always used in custom designs, so a system designer producing many thousands of units would typically require a custom carrier balanced to the system requirements while keeping a keen eye on product costs. The custom part of the COM design is the COM carrier card, the cost of which is affected by component or connector counts; a simple carrier design for product equipment may only require a serial, Ethernet and video connector. All projects have their own custom requirements; however a base carrier design may be used to define other custom variants, which may reduce the cost of production for each custom design.

Designers of PC/104 systems need to determine if their project is a custom project before taking the next steps in the system design using COM. If the project does not require custom design, it’s normally better to use a standard PC/104 off-the-shelf product.

The Qseven standard defines mechanical and form factor information only; the specification may be downloaded from http://www.qseven-standard.org. The Qseven standard does not cover software requirements of the Qseven architecture, as this would be outside the confines of the standard. Software is a custom option, chosen by customers for their platforms and would use specific operating systems with associated devices drivers or board support packages. However, it’s important from a system maintenance and company-wide product viewpoint to select a Qseven solution that has common driver, BIOS and utilities across all COM architectures to ensure that maintenance of the system products becomes consistent across all form factors.

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The Qseven standard has been specifically developed to utilize the latest low-power-consuming technology and to meet the demand for small form factors. It has a typical power consumption of less than five watts, is barely larger than a credit card, has integrated functions for battery and ACPI 3.0 power management and features real-time watchdog support. With these specifications, the Qseven modules are optimized to enable all mobile applications.

The Intel® Atom™ processor E6xx series-based Qseven modules feature fast serial differential interfaces such as USB, PCI Express and Serial ATA. In total, it supports 6x USB 2.0, 2x SATA, 1x SDIO, 3x PCIe, LPC bus, I²C bus, Gigabit Ethernet, high-definition audio, SPI and CAN bus interfaces. The CAN bus and SPI interfaces are new additions to the Qseven standard and utilize previously unused pins. (See Figure 4.)

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Controller Area Network (CAN) is a 1Mbps technology on differential twisted pair cabling with termination at both ends. CAN is now used extensively on commercial, industrial and even military applications, as the technology is cheap when compared to similar technologies such as MIL STD 1553. MIL STD 1553 is much more expensive, but is deterministic, while CAN technology as it stands is not deterministic. However, MIL CANappears to have resolved these determinism issues.

The most significant advancement of the Intel Atom processor E6xx series is that the graphics, high-definition audio, memory controller, SM Bus interface and PCI Express interfaces are inside the processor. This is significant from a software processing capability, as random access memory (RAM) access by software is directly from the processor, which will increase processing performance, even on ultra-low-power processors. Another significant improvement in the processor I/O hub architecture is the massive increase in bandwidth between the processor and Intel® Platform Controller Hub EG20T by using a PCI Express interface.

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In short, from a software-engineering and system-response aspect, this new Intel processor has broken some of the more traditional bottlenecks, such as the typical 400/800MHz front-side bus interface from processor to input output devices such as USB, SATA and Ethernet. PCI Express bandwidth greatly optimises software throughput within the system.

In summary, PC/104 system providers that adopt the Qseven COM technology approach will benefit from a range of fully scalable products, much faster time to market, the latest Intel® technology ahead of the competition and lower costs on larger projects. This importantly increases margins in real terms and maintainability of systems in the field becomes far less complicated.


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Fischer earned a Dipl.Ing (FH) degree from the University of Applied Sciences in Munich, Germany. He has more than 13 years of experience in hardware design, EMC, avionics engineering and graphics, and has previously held positions with ATI Professional Graphics in Germany, as well as IndustrieHanda Consulting and Engineering.