CompactPCI Serial

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CompactPCI Serial is an industry standard for modular computer systems. It is based on the PICMG 2.0 CompactPCI standard, which uses the parallel PCI bus for communication between the individual modules in a system. In contrast, CompactPCI Serial uses only serial point-to-point connections . CompactPCI Serial was officially accepted by the PCI Industrial Computer Manufacturers Group PICMG as PICMG CPCI-S.0 CompactPCI Serial in March 2011 . The mechanical concept is based on the standards IEEE 1101-1-1998 and IEEE 1101-10-1996 (19 ″ technology). CompactPCI Serial describes various connectors that allow high data throughput. The technology standard that replaces the parallel CompactPCI contains a further specification called PICMG 2.30 CompactPCI PlusIO. That is why CompactPCI Serial and CompactPCI PlusIO as a whole were initially also called CompactPCI Plus . The first working title of the PICMG for CompactPCI Serial was CPLUS.0.

history

At the beginning of the 21st century, fast, serial point-to-point connections became the state of the art and are gradually replacing the classic bus architecture in computers. The CompactPCI standard does not offer a standardized solution for the type of modular networking. That is why CompactPCI Serial is emerging as a standard. It introduces a serial topology and at the same time retains the basic concepts of CompactPCI.

Star architecture

Thanks to the chipset architecture, the structure of computers is changing away from bus-based connections between interface controllers towards a star architecture based on serial two-point connections. CompactPCI Serial implements this architecture. One system slot can control up to eight peripheral slots. Two of these connections can be implemented as PCI Express Fat Pipes (x8). At the same time, CompactPCI Serial does not need bridges, switched fabrics or special backplanes. The star connection includes PCI Express, SATA / SAS and USB as standard.

Ethernet as a meshed network

With fully meshed Ethernet according to the Ethernet standard IEEE 802.3 , CompactPCI Serial can connect nine modules in one system (one system and eight peripheral slots). The specification is thus optimized for symmetrical multiprocessing and redundant systems .

Interfaces

The system slot on the PICMG CPCI-S.0 supports the following interfaces on the rear panel connector:

The peripheral slot of the PICMG CPCI-S.0 supports the following interfaces on the rear panel connector:

  • 1 × PCI Express
    • Up to 8 lanes per link
  • 1 × SATA
    • Supported by a special SGPIO bus (specification SFF-8485)
  • 1 × USB 2.0
  • 1 × USB 3.0
  • Up to 8 Ethernet 10GBASE-T interfaces
  • geographic addressing

Power supply from CompactPCI Serial

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

Backplane connector from CompactPCI Serial

The PICMG working group working on the standard has proposed a higher density backplane connector type. Its grid dimension is 2 mm × 1.4 mm and it supports higher transmission rates of up to 12 Gbit / s without the need for bridges or switches. It contains up to 184 pairs of pins on a 3U card. A big difference compared to CompactPCI is that with CompactPCI Serial the pin header is located on the module, while the socket is located on the backplane. This approach is intended to make the standard more robust by avoiding bent pins on the backplane. If a connection pin fails, only the plug-in card has to be replaced. The CompactPCI Serial system slot has six connectors: P1 to P6. In the case of peripheral cards, only P1 is mandatory, while P2 to P6 can be optionally equipped.

Rear I / O concept

A CompactPCI Serial peripheral slot only has a small connector with 6 rows of contacts for power supply and signals. The rest of a 3U Eurocard is free for user-defined I / O and offers 128 differential contact pairs or 384 contacts. 6 U double euro cards provide the entire upper area of ​​the assembly for user-defined I / O, just like PICMG 2.0 CompactPCI cards of this size. One advantage of the new architecture is that the front and rear I / O cards are plugged into one another. In contrast to CompactPCI, neither a midplane nor a transfer connector is required here.

Compatibility and Migration

CompactPCI PlusIO hybrid system with 4 slot CPCI + 4 slot CPCI PlusIO

The mechanical specification of PICMG CPCI-S.0 CompactPCI Serial corresponds 100% to PICMG 2.0 CompactPCI, with the exception of the new backplane connector. Since the two standards have different topologies, there is no direct "bus compatibility". This is why PICMG has also developed an expansion for 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 has a fixed definition of fast, serial I / O interfaces on the rear panel connector J2. The connector type of the J2 is also new. It is compatible, but supports a higher data throughput than CompactPCI. Hybrid backplanes support several modules of the three different standards PICMG 2.0, 2.30 and CPCI-S.0.

Web links

Individual evidence

  1. ↑ PICMG: "CompactPCI Serial Overview" (English)
  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. ↑ Origin and concept of the CompactPCI Plus bus standard . ELECTRONICS PRACTICE. January 14, 2009. Retrieved August 25, 2010.
  5. ↑ Hybrid backplanes for CompactPCI & CompactPCI Plus . ELECTRONICS PRACTICE. July 21, 2009. Retrieved August 25, 2010.