[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re[2]: Termination of Bussed signals (CompactPCI)



On August 5, Rich Mellitz wrote:

>What's this? Does Compact have their own PCI Spec? The rules for PCI (4.4.3 ff)
>state that you get 1.5" (2.0" on 64 bit systems) to your PCI chip on a
>PCI plugin card.  The spec also states that you can not attach any discrete
>devices to the PCI signals on the cards.

Because CompactPCI is designed by the PCI Industrial Manufacturers Group for 
industrial and embedded applications, there was a need to adapt some parameters 
of the 'classic' PCI Spec to meet the requirements. One important design goal of
CompactPCI was to support up to 8 slots with a passive backplane - without using
PCI-Bridges! Therefore it was necessary to add extra bus signal terminations (10
ohms) to the PCI signals. AFAIK this decision is based on computer simulation 
results. Another different parameters are connector types, PCB form factor, 
front panel, Hot Swapping... 
The specification and FAQ of CompactCPI can be found at 
http://www.compactpci.com/

Another PCI based specification for industrial applications is the IndustrialPCI
Spec (IPCI), developed by the German SIPS group. Because IPCI limits the number 
of backplane slots to 5, there is no need for extra bus signal termination. 
For more info about IPCI go for 
http://ourworld.compuserve.com/homepages/Peter_Lippert/ipcispec.htm

Roland Knapp
Conware GmbH
knapp@conware.de

 







íTB