Kontron CPCI Backplane - Manual (Page 24)

General CPCI Backplane
Page 10 © 2005 Kontron Modular Computers GmbH ID 24229, Rev. 03
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9.03.UG.VC.051007/14565
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P R E L I M I N A R Y
3.3 Signalling Environment
Each CompactPCI backplane supports a 5V or a 3.3V signaling environment – V(I/O), and PCI
allows for two types of buffer interfaces for interboard connection. However, a gradual shift to
3.3V is occurring as the semiconductor industry shifts to the lower power interface for speed
and power dissipation reasons. For this reason, the Kontron Modular Computers system back-
planes are also designed for 3.3V usage.
3.4 Rear I/O Connectivity
Rear I/O capability is a function of the individual backplane. Kontron Modular Computers pro-
vides both 3U and 6U backplanes with rear I/O functionality. Refer to Table 3 for information
regarding the rear I/O capability of Kontron’s backplanes. For the exact configuration (slots,
connectors, and pinouts) of rear I/O backplanes refer to the appropriate backplane product doc-
umentation.
3.5 Flexible Grounding Option
With certain backplane types it is possible to select electrical isolation or connection between
the bus GND and the backpanel support PE (rack), thanks to the fact that every second fasten-
ing hole of backplanes is non-conducting. If only these fastening holes are used, there is no
electrical connection between GND and PE on the system bus. If additional holes are used, a
multi-point connection is created such as may be required for EMI protection purposes.
3.6 Rack Dividers
3U boards may be used in a 6U rack. If one or two 3U backplanes are used, a middle bar is
used to hold the 3U boards in place. If the 3U boards are installed on a 6U backplane, a split
kit must be used in place of the backplane’s P3 connector(s). For further information concern-
ing split kits and middle bar separation refer to the appropriate product documentation.
Warning!
Using both 3.3V and 5V boards within the same system may result in damage
to your equipment. Please note that the presence of only one 5V board deter-
mines a 5V signaling environment. The default setting is 5V.
When changing the signaling environment from 5V to 3.3V or viceversa,
please make sure that coding keys of the appropriate color are used (see Cod-
ing Keys section of this chapter).