Kontron ETXexpress-WPM, Руководство пользователя

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ETXexpress-WPM User’s Guide page 19
ETXexpress Reference Documents
This User Guide serves as one of three principal references for an ETXexpress COM
design. The other two references include:
Š
The COM Express™ Specification , which defines the two COM Express™ form
factors (Basic and Extended), the five module types, pin-outs, and signals. You
should read this document first. You can find the COM Express™ Specification
on the PICMG (PCI Industrial Computer Manufacturers Group) Web site:
www.picmg.org. There is a fee for the document. All Kontron ETXexpress
Modules are based upon the COM Express™ Specification. Kontron played a
leading role in developing the COM Express™ Specification.
Š
The ETXexpress Design Guide serves as a general guide for carrier board design,
with a focus on maximum flexibility to accommodate a range of ETXexpress
modules.
About PCI Express
PCI Express has become the primary data path for upcoming x86 based systems. Non
PCI Express components such as PCI plug-in cards can still be supported with the PCI
2.1 32-bit interface. ETXexpress COMs will continue supporting the PCI bus for legacy
applications.
PCI Express is an international I/O interconnect bus standard that expands on and
doubles the data transfer rates of the original PCI bus standard. PCI Express is a two-
way, serial connection that carries data in packets along two pairs of point-to-point data
lanes, compared to the single parallel data bus of traditional PCI that routes data at a
set rate.
Initial bit rates for PCI Express reach 2.5Gb/s per lane direction, which equate to data
transfer rates of approximately 200MB/s. A group of companies, headed by Kontron,
developed the COM Express™ Specification so that high-speed interconnects such as
USB 2.0 and Gigabit Ethernet would have an I/O architecture suitable for their high
transfer speeds.