TABLE OF CONTENTS CompactPCI is just an industrial strength version of the same PCI bus found in any contemporary personal computer. It is electrically compatible with PCI and uses the same protocol. For reliability and ease of repair it is based on a passive backplane rather than the PC motherboard architecture. It utilizes Eurocard mechanics, made popular by VME, and a shielded pin-and-socket connector with 2 mm pin spacing.
Perhaps its most interesting feature is that it supports up to eight slots per bus segment rather than the four slots typically found in conventional PCI implementations. This is due to the low capacitance of the connector. Extensive simulations were done in the course of developing the CompactPCI specification to verify that it could indeed support eight slots.
CompactPCI supports both 32- and 64-bit implementations at up to 33 MHz clock frequency for the full eight slots and 66 MHz over a maximum of five slots.
Advances in desktop PCs have a way of "migrating" into the world of industrial computing. In all cases, the motivation is to leverage the efficiencies of scale resulting from the enormously high volumes inherent in the desktop world. So it is with CompactPCI.
A wide range of reasonably priced PCI silicon is available for use in CompactPCI devices. VME silicon can't begin to match the volume of PCI and so remains generally more expensive.
The same considerations apply to software. Popular operating systems and applications already support PCI, particularly with respect to Plug-and-Play configurability.
Finally,...
