PC module looks to low-power processors
A pair of board-level computer makers have added one more embedded-PC format to the growing list of prospective standards in the industrial-control field. Formed by veterans of Jumptec who developed the ETX format, Germany-based Congatec has joined forces with Italian supplier Seco to push the “legacy-free” QSeven format.
Christian Eder, marketing director of Congatec, said the new format is “for new power saving processors that do not support parallel interfaces. For them, we decided to create something from scratch”.
The name comes from the size of the modules, which are 7cm x 7cm, and they only support serial I/O standards such as PCI Express and Serial ATA disk drives. The existing standards for plug-in embedded PC cards have dedicated pins on their connectors for old parallel interfaces that, in many cases, are no longer used. It does not support as many PCI Express lanes four instead of twenty two but the QSeven is intended to compete with boards designed to the older interface. Although only two companies currently back QSeven, Eder said the plan is to recruit more backers, as happened with ETX and COM Express in earlier years. “We are inviting other companies to take part and join the QSeven club.”
Cost was one aspect of the QSeven module design. “The first thing we looked for was a new connector,” said Eder. “The COM Express connector is good but it is expensive. We found the MXM, which is used for notebook graphics cards.”
Instead of the two-part connector used by COM Express, the MXM is an edge connector, keyed to prevent modules from being inserted upside down. “It is rugged and specified to high speed operation,” Eder claimed. Cost savings come from only having to use one $4 connector in place of the two $8 connectors needed by COM Express.
Cooling was another consideration in the design. The format is designed so that internal layers of the PCB can act as a heat spreader. A metal plate at one end helps conduct heat out to the chassis. “You can use an Intel Menlow with this without any further cooling,” Eder claimed.
To try to head off the interoperability problems that have plagued the COM Express market something that has led standards group PICMG to write a set of interoperability guidelines Eder said the hardware specification for QSeven is more tightly defined. There is also a software application programming interface for some of the non-PC I/O links such as I2C. “One is also there for the display interface,” said Eder.
Image: Congatec's Christian Eder holds up a QSeven module