PDF of this tutorialCompactPCI offers a substantial number of benefits for developers interested in building telco-grade applications. CompactPCI systems offer the durability and maintainability required for network applications. At the same time, they can be built using standard, off-the-shelf components and can run almost any operating system and thousands of existing software applications without modification. Other advantages of CompactPCI are related to its Eurocard form factor, durable and rugged design, hot swap capability, and compatibility with the CT Bus.
Eurocard Form Factor
CompactPCI boards use the Eurocard form factor, field-proven for use in telco applications worldwide.
- Two card sizes are available:
- 3U (100 mm × 160 mm) with single 220-pin connector
- 6U (160 mm × 233 mm) can support up to three additional connectors
- Separates the boards from the cables
- Boards are designed for front loading and removal
- No need to disconnect and reconnect cables when replacing a failed network board
- Reduces the chance of disrupting other cables and boards inside the chassis
- Outwardly exposed lights
- Lights are visible to maintenance staff
- Out-of-service boards or boards without power can easily be detected and replaced
- Lights may provide diagnostic information such as failure of self-tests
- High densities in a compact server
- Size of boards and optimal spacing means more resources in a smaller package
- Vertically spaced boards
- Vertical spacing provides more efficient cooling because hot air flows upward
Durable and Rugged Design
The CompactPCI system architecture was specifically designed with telco environments in mind resulting in a network-equipment building standards (NEBS)–compliant, durable, and rugged form factor.
- Boards are held firmly in place by their connectors, guides on both sides, and a metal face plate that screws or latches onto the cage.
- Pin and socket connectors on the boards are more reliable and have better shock and vibration characteristics than other form factors, such as PCI.
- I/O cables are in the rear of the chassis, where they are less liable to accidental interference.
CT Bus
The CT Bus is a time division multiplex (TDM) bus that provides 1024, 2048, or 4096 time slots for exchanging voice, fax, or other network resources on the CompactPCI backplane. The CT Bus lets developers build large, distributed, open CT systems in public network and customer-premises environments.
The particular value attached to CompactPCI by the CT industry is closely connected to the development of interoperability standards. Both the SCbus and multivendor integration protocol (MVIP)–90™ were developed to let CT applications control resource boards (voice, fax, text-to-speech, etc.) without occupying the system bus. This allowed greater speed, efficiency, and scale in application design and propelled a new wave of CT services. The Enterprise Computer Telephony Forum (ECTF) then developed the H.100 hardware compatibility specification that defined the CT Bus, a high-performance mezzanine bus. The CT Bus works with both SCbus– and MVIP–compatible products. The ECTF implementation of the CT Bus for CompactPCI bus is called the H.110 standard.
Figure 1. H.110 CT Bus
CompactPCI Objectives
- CompactPCI devices are fully compliant with PCI rev. 2.0.
- CompactPCI uses standard PCI chip sets.
- CompactPCI uses a passive backplane architecture.
- CompactPCI is processor independent.
- CompactPCI provides plug-and-play facilities.
- CompactPCI uses an industrial card format.
- CompactPCI uses a high-density pin and socket connector.
- CompactPCI maximizes the number of PCI slots.
- CompactPCI defines a hot-swapping mechanism.
- CompactPCI can bridge to other PCI bus and I/O buses (G-64, VME, subscriber trunk dialing [STD]).
The Power of PCI
The PCI bus has been defined by Intel as a local bus providing an ultra-fast direct link between the CPU and high-speed peripherals devices. PCI has been adopted by almost all CPU manufacturers and is at the core of all modern Intel® Pentium®, Digital Equipment Corporation (DEC) Alpha*, and IBM/Motorola PowerPC* systems.
High Performance
- 32-bit and 64-bit bus with peak bandwidth at 264 Mbps
- Concurrent processing with processor/memory subsystems
- Synchronous bus operation at a 25 to 33 MHz clock
- Low power consumption (5V or 3.3V technology)
Low Cost
- Optimized for direct interconnection of PCI chips to the bus
- Multiplexed architecture reduces pin count and package size
- Mass-produced components with decreasing selling price
Ease of Use
- PCI peripheral boards contain configuration for automatic plug-and-play
- PCI bus topology can be expanded using transparent PCI–to–PCI bridges
- Hidden overlapped central arbitration
- Broad operating system and application software support
Industrial Form Factor
Industrial computers must be capable of operating reliably in the most demanding environment. They should tolerate heat, dirt, and high shocks and vibrations, with meantime between failures (MTBF) measured in tens of thousands of hours. CompactPCI defines a single or double Eurocard (3U or 6U) board format. Boards mount vertically for best cooling characteristics, with card extractors and user I/O connectors in the front of the card. CompactPCI uses a standard Eurocard chassis available from many vendors.
Figure 2. Eurocard Chassis
High-Density Connector
The CompactPCI connector, standardized by International Electrotechnical Commission (IEC)–1076-4, is widely used in the telecommunication industry and is available from several leading manufacturers (AMP, ERNI). The 235 pins (47 pins by five rows) of the CompactPCI connector include all the PCI signals (32 bit and 64 bit) and 40 pins reserved for future extension. A 3.3V/5V keying mechanism prevents incorrect insertion and accidental damage.
Hot Swapping
The CompactPCI specification accommodates a methodology for live insertion and removal of the boards while the system is operating. Hot swapping is achieved using staged pins for power and PCI signals. This feature allows the maintenance and the upgrade of a system while running.
Bridging to Other Buses
CompactPCI passive backplanes can be bridged to any dedicated I/O bus, such as G-64, PC/104, VME, STD, telecom, or proprietary buses. Bridge circuitry is used to interface the address, data, and control lines of the different buses. CompactPCI backplanes can also be expanded to 15 or more PCI slots using off-the-shelf PCI–to–PCI bridge chips. Hybrid CompactPCI systems with high-performance PCI functions and low-cost interfaces on I/O buses can be built in standard 3U or 6U rack enclosures.
An Industrial System Solution
CompactPCI rack enclosures combine small and sturdy packaging, making them ideally suited for embedded and industrial applications. GESPAC rack enclosures also have the electromagnetic compatibility (EMC) approval according to the European legislation.
CompactPCI systems use small and rugged 3U Eurocard enclosures with swappable power supplies, fan units, and a four-to-eight-slot CompactPCI backplane. Wider enclosures (up to 19 inches) are available for I/O–intensive systems.
