Table of Contents:

Definition and Overview

1. Background and Beginnings

2. A New Standard

3. The CompactPCI Backplane

4. Connectivity and Capacity

5. Secure Access: The Key to Operational Convenience

6. The Hot Swappability Revolution

7. Software, Integration, and Processes

8. References

Self-Test

Glossary

PDF of this tutorial

As indicated, the backplane is crucial to any scalable system. CompactPCI defines a new backplane technology that confers a number of key benefits to manufacturers. These benefits are based upon the combination of three key factors:

• PCI silicon support
• 2-mm IDE connectors
• large form factor

The PCI standard is a bus standard developed for PCs by Intel that can transfer data between the CPU and card peripherals at much faster rates than are possible via the ISA bus (e.g., about 132 Mbps as opposed to 5 Mbps). PCI was originally designed for standardizing the interfaces available on chips to be used on PC–compatible peripherals and was unique in that it utilized silicon. Importantly, PCI was designed with limitations to the maximum capacity of the bus and to the electrical loading it would require. These considerations helped minimize the costs of the bus interface.

PCI was rapidly adopted by other vendors and became the most common bus interface for such chips. Despite becoming the established interface, offering high-speed data transfer, PCI lacked the higher density available from systems utilizing VME, as only four cards could be supported within a system. CompactPCI was a solution to this set of problems, given that it adopted the proven European form factor successfully utilized in VME systems.

CompactPCI uses a vertically mounted backplane consisting of five connectors, as is defined in the PICMG's CompactPCI specification 2.0. This method of mounting is significantly more robust that that available from a standard PC and also provides better access for cooling because air can flow past more easily. Telecommunications applications often require the use of large amounts of digital signal processors (DSPs), which are usually heat intensive; thus, cooling is essential.

Cards are inserted into the physical bus interface from the front of the unit, enabling straightforward access. Furthermore, the vertically orientated bus provides the possibility of access from two sides. This point is highly significant, as is explored in Topic 4. All in all, a CompactPCI chassis offers a rugged, secure, and highly reliable platform in which to insert communications cards for demanding applications.