CompactPCI Serial

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CompactPCI Serial is an industrial standard for modular computer systems. It is based on the established PICMG 2.0 CompactPCI standard, [1] which uses the parallel PCI bus for communication among a system's card components. In contrast to this, CompactPCI Serial uses only serial point-to-point connections. CompactPCI Serial was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG CPCI-S.0 CompactPCI Serial in March 2011. Its mechanical concept is based on the proven standards of IEEE 1101-1-1998 [2] and IEEE 1101-10-1996 [3] (19" technology). CompactPCI Serial includes different connectors that permit very high data rates. The new technology standard succeeding parallel CompactPCI comprises another specification called PICMG 2.30 CompactPCI PlusIO. This is why CompactPCI Serial and CompactPCI PlusIO as a whole were also called CompactPCI Plus. PICMG's first working title of CompactPCI Serial was CPLUS.0. (See also #Compatibility and Migration.) CompactPCI Serial backplanes and chassis are developed by Schroff, Elmа, and Pixus Technologies companies, as for the CompactPCI Serial board level electronics – they are developed by MEN Mikro Elektronik, Fastwel, EKF, Emerson Embedded Computing, ADLINK, and Kontron.

Contents

History

Fast serial point-to-point connections have become the state-of-the-art technology and are gradually replacing the classic bus architecture in computers. The CompactPCI standard as it is now does not offer a standardized solution for the kind of modular, serial connectivity requested for the future. This is why CompactPCI Serial was defined as the new future standard. It introduces a serial topology while keeping the proven basic concepts of CompactPCI. [4]

Star Topology

Thanks to modern chipset architecture, the structure of computers is slowly changing from bus-based interconnections between interface controllers to a star topology built up of serial point-to-point connections. CompactPCI Serial incorporates this star architecture: one system slot can control up to eight peripheral slots. Two of these connections can be PCI Express x8 fat pipes. At the same time, CompactPCI Serial does not need bridges, switched fabrics, or special backplanes. The star connection by standard includes PCI Express, SATA/SAS, and USB.

Ethernet Full Mesh Architecture

CompactPCI Serial can connect a total of nine cards in a system (one system slot, eight peripheral) through a full Ethernet mesh that supports the IEEE 802.3 Ethernet standard. In this way the new specification is optimized for symmetrical multiprocessing and redundant system topologies.

Interfaces

The PICMG CPCI-S.0 system slot supports the following interfaces at the backplane connectors:

The PICMG CPCI-S.0 peripheral slot supports the following interfaces at the backplane connectors:

Power Supply of CompactPCI Serial

PICMG CPCI-S.0 defines a single 12-V power supply both for system slots and peripheral slots.

Backplane Connectors of CompactPCI Serial

The PICMG subcommittee drafting the standard has proposed a new, denser backplane connector type with a 2 mm x 1.4 mm pitch that supports higher transfer rates of up to 12 Gbit/s without a need for bridges or switches. It offers up to 184 pin pairs on a 3U board. A major difference compared to CompactPCI is that with CompactPCI Serial the plug connector is on the board, while the receptacle is on the backplane. This approach is intended to make the standard more robust by avoiding twisted pins on the backplane: If a pin fails, only the plug-in board must be exchanged. The system slot of CompactPCI Serial has six connectors: P1 to P6. On peripheral boards only P1 is mandatory, while P2 to P6 are optional.

Rear I/O Concept

A peripheral CompactPCI Serial slot only has a small connector with 6 rows of contacts for power and signals. The remainder of a 3U single Eurocard is free for user-defined I/O and offers a total of 128 differential contact pairs or 384 contacts. This is significantly more than in 32-bit CompactPCI. 6U double Eurocards provide the entire upper section of the board for user-defined I/O, as do PICMG 2.0 CompactPCI boards of this size. An advantage of the new architecture is that front and rear I/O boards are inserted directly into one another. By contrast to CompactPCI, no midplane or transfer connector is needed here, which reduces costs and increases system flexibility.

Compatibility and Migration

The mechanical specification of PICMG CPCI-S.0 CompactPCI Serial is 100% compliant with PICMG 2.0 CompactPCI except for its new backplane connectors. Since the two standards have a different topology, there is no direct "bus compatibility". For this reason, PICMG has also created an extension to CompactPCI: PICMG 2.30 CompactPCI PlusIO. This standard is intended as a migration path from CompactPCI to CompactPCI Serial. It is 100% compatible with CompactPCI but includes a fixed definition of fast serial I/O interfaces at its backplane J2 connector. Also, it has a new J2 connector that is compatible but supports higher data rates compared to CompactPCI. Hybrid backplanes support several cards of the three different standards PICMG 2.0, 2.30, and CPCI-S.0. [5] [6]

CompactPCI Serial Space

In August 2017, PICMG ratified the CompactPCI Serial Space specification CPCI-S.1 R1.0, which provides a highly ruggedized implementation of CompactPCI Serial. It is used in satellites as the payload controller as well as ground-based control systems.

See also

Related Research Articles

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<span class="mw-page-title-main">Eurocard (printed circuit board)</span> Standard for PCBs which may be interconnected in a rack mounted chassis

Eurocard is a European standard format for printed circuit board (PCB) cards that can be plugged together into a standard chassis which, in turn, can be mounted in a 19-inch rack. The chassis consists of a series of slotted card guides on the top and bottom, into which the cards are slid so they stand on end, like books on a shelf. At the spine of each card is one or more connectors which plug into mating connectors on a backplane that closes the rear of the chassis.

<span class="mw-page-title-main">Motherboard</span> Main printed circuit board (PCB) for a computing device

A motherboard is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allows communication between many of the crucial electronic components of a system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals. Unlike a backplane, a motherboard usually contains significant sub-systems, such as the central processor, the chipset's input/output and memory controllers, interface connectors, and other components integrated for general use.

<span class="mw-page-title-main">Expansion card</span> Circuit board for connecting to a computer system to add functionality

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<span class="mw-page-title-main">PCI Express</span> Computer expansion bus standard

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<span class="mw-page-title-main">Serial ATA</span> Computer bus interface for storage devices

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<span class="mw-page-title-main">Single-board computer</span> Computer whose components are on a single printed circuit board

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<span class="mw-page-title-main">CompactPCI</span> Computer bus interconnect for industrial computers

CompactPCI is a computer bus interconnect for industrial computers, combining a Eurocard-type connector and PCI signaling and protocols. Boards are standardized to 3U or 6U sizes, and are typically interconnected via a passive backplane. The connector pin assignments are standardized by the PICMG US and PICMG Europe organizations. The connectors and the electrical rules allow for eight boards in a PCI segment. Multiple bus segments are allowed with bridges.

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<span class="mw-page-title-main">VPX</span> Standards for connecting components of a computer

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CompactPCI PlusIO is an extension to the PICMG 2.0 CompactPCI industrial standard for modular computer systems. CompactPCI PlusIO was officially adopted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG 2.30 CompactPCI PlusIO in November 2009. Being 100% compatible with CompactPCI, PICMG 2.30 defines a migration path to the future CompactPCI Serial standard. It defines a fixed rear I/O pin assignment that focuses on modern, fast serial point-to-point connections. The new technology succeeding parallel CompactPCI comprises both CompactPCI Serial and CompactPCI PlusIO.

<span class="mw-page-title-main">PICMG 1.3</span>

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M.2, pronounced m dot two and formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion cards and associated connectors. M.2 replaces the mSATA standard, which uses the PCI Express Mini Card physical card layout and connectors. Employing a more flexible physical specification, M.2 allows different module widths and lengths, which, paired with the availability of more advanced interfacing features, makes M.2 more suitable than mSATA in general for solid-state storage applications, particularly in smaller devices such as ultrabooks and tablets.

<span class="mw-page-title-main">SATA Express</span> Computer device interface

SATA Express is a computer bus interface that supports both Serial ATA (SATA) and PCI Express (PCIe) storage devices, initially standardized in the SATA 3.2 specification. The SATA Express connector used on the host side is backward compatible with the standard SATA data connector, while it also provides two PCI Express lanes as a pure PCI Express connection to the storage device.

MicroTCA is a modular, open standard, created and maintained by the PCI Industrial Computer Manufacturers Group (PICMG). It provides the electrical, mechanical, thermal and management specifications to create a switched fabric computer system, using Advanced Mezzanine Cards (AMC), connected directly to a backplane. MicroTCA is a descendant of the AdvancedTCA standard.

References

  1. PICMG 2.0 Archived June 26, 2012, at the Wayback Machine
  2. IEEE 1101-1-1998, IEEE Standard for Mechanical Core Specifications for Microcomputers Using IEC 60603-2 Connectors
  3. IEEE 1101-10-1996, IEEE Standard for Additional Mechanical Specifications for Microcomputers Using the IEEE 1101.1-1998 Equipment Practice
  4. "Teaching old dogs new serial I/O tricks on CompactPCI". Embedded.com. 2011-04-19. Retrieved 2015-09-25.
  5. "Teaching old dogs new serial I/O tricks on CompactPCI". Embedded.com. 2011-04-19. Retrieved 2015-09-25.
  6. "Mixed Doubles: CompactPCI Serial and CompactPCI 2.0". Intel. 2011-06-27. Retrieved 2015-09-25.