There is a permanent demand for computer systems, which are more powerful
and smaller in size than the previous generation. At the same time the
available components and interfaces shall meet customers requests.
One answer to these demands are the so called Computer On Modules,
or "COM" for short. These are small modules, equipped with the core
components of modern computers. The module harbours the CPU, the DRAM
and also the BIOS in Flash Memory.
Such modules have a defined form factor as well as specific connectors
to a carrier board. The connectors provide a rich set of interfaces.
It is the carrier board which makes the design task flexible.
The implementer decides which connectors and interfaces are available
on the carrier board. Components aren't realised when they are not required.
Such results in a system with the smallest possible form factor.
Qseven™ is a new standard, which is defined for very small modules
(70×70mm²) and also low power consumption. The standard is targeted
for the ultra-mobile generation of 45nm technology. Since these new processors
and chipsets are designed legacy-free, the Qseven standard is legacy-free also.
Qseven provides PCI Express and PEG, Serial ATA and SDIO.
The maximum allowed power consumption is 12 Watt only, which emphasizes the
intended targets as mobile devices. Besides the targets of the specifications,
Qseven systems are quite fine where small size and low power consumptions is
an important design goal.
COM Express™ is a PICMG standard which defines a COM module as
a ready component to be placed on the carrier board. The standard
supports legacy buses like PCI, PATA and LPC. The buses are connected
to the carrier board via 440 pin connectors. The carrier board then
implements the legacy components like PS/2, Floppy etc. as required by
the target application.
The same standard also places modern high speed interfaces on the connectors,
like PCI Express, SATA, Gigabit Ethernet and USB 2.0.
So designers can choose from many options to make their final system.