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Paving the way for ruggedised, standardised COMs

Posted: 22 Aug 2013 ?? ?Print Version ?Bookmark and Share

Keywords:embedded systems? Computer-On-Module? CPU? FPGAs? PICMG COM.0?

ESMexpress not only allocates specific tasks to the CPU module versus the carrier board, but also incorporates a resource-sharing concept of using available IP cores to configure field-programmable gate arrays on the carrier board to enhance specific functionality. The fixed assignment of the processor and the SDRAM functions on the CPU module eliminates the need for complex and expensive changes to that unit. Conversely, licensing IP cores to execute specific I/O requirements through carrier board FPGAs is a quicker and more affordable way to adapt to custom application inputs. Using FPGAs also allows more I/O to be achieved in less space C an important consideration for small form factor applications.

Regardless of the microprocessor platform selected for an ESMexpress CPU module or any other customised attributes of the carrier board, the VITA 59 RSE standard includes a list of attributes for rugged performance in harsh operating environments:

Connectors. The pin assignment on all ESMexpress CPU modules is fixed to guarantee interchangeability with any carrier board that meets the VITA 59 standard.

Electrical signals from the module board are distributed on two robust 120-pin connectors on the board's bottom side, a design that has been approved by major railway and avionics companies.

The connections are defined only for high-speed modern serial buses such as PCI Express, Gigabit Ethernet, USB, SATA, SDVO, LVDS, HD audio, and several utility signals as well as a single 12 V power supply.

Cooling. While heat build-up is a function of processing power, several factors in the ESMexpress solution help alleviate cooling concerns in compact spaces or extreme ambient temperatures. For example, carrier modules with low-voltage chips minimise heat generation, even at processing speeds up to 1.6GHz.

More important, however, is that the mechanical configuration and the combined conduction/convection cooling considerations of the VITA 59 design accommodate functional operating temperatures ranging from -55C to +125C. What makes that possible is the built-in heat transfer properties of the CPU module design, the choice of connector, and the solid connections between the chip, the module frame and cover, and the carrier board.

Heat from the CPU is transferred to the metallic top cover and then to six cooling tabs that mate with the module frame for conductive cooling. Supplemental cooling is also possible by applying a heat sink to the top of the module cover.

Environmental durability. Robust connectors, soldered components, and the solid mechanical connections that facilitate convection cooling also enable ESMexpress modules and carrier boards to withstand substantial shock up to 15 g/11 ms and sinusoidal vibration of 1 g/10Hz to 150Hz.

The availability of conformal coating when needed enhances the module's ability to withstand harsh, wet, or chemical-laden environments. So whether end-use applications are in external or mobile applications or in a harsh industrial environment, VITA 59-compliant solutions offer greater robustness than other small form factor COM designs.

EMC protection. The 100% sealed metal housing design of the ESMexpress module also provides exceptional EMC protection, conforming to EN 55022 for radio disturbance, to EN 55024 and EN 61000-4-2 for electrostatic discharge, and EN 55024 and EN 61000-4-4 for burst.

Within the parameters of the VITA 59 RSE standard, the possibilities for ESMexpress implementation are extensive. Compact form factors make for an attractive resource for space-constrained applications in fixed or mobile computing environments. Rugged design and construction characteristics open up the versatility of the COMs concept to a wider range of applications than ever before:

???Signal, control, or passenger information systems in railway applications
???Industrial robotic applications, from plastics production to semiconductor clean-room production and general automation
???Extreme industrial environments
???Demanding mobile computing needs such as medical equipment or transportation applications
The broad range of high-speed serial interfaces C from USB and SATA to Ethernet and PCI Express C plus the versatility of FPGA customisation provides cost-effective adaptation to a wide range of computing environment needs.

As with the COM Express standard, ESMexpress features interchangeable CPU modules and carrier boards that offer end users flexibility to mix and match the ideal elements from different manufacturers as they adopt the finalized VITA 59 standard.

About the author
Barbara Schmitz has served as Chief Marketing Officer of MEN Mikro Elektronik. She graduated from the University of Erlangen-Nrnberg. Later, she studied business economics in a correspondence course at the Bad Harzburg business school and followed an apprenticeship in Marketing and Communications in Nuremberg.

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