CompactPCI® Serial Overview

cpcis2As PCI bus technology has moved from a parallel interface to fast serial point-to-point interconnects, the popular and very successful parallel CompactPCI® specification PICMG 2.0 was significantly extended and enhanced by the newer CompactPCI® Serial standard, PICMG CPCI-S.0, in 2011. Both 3U and 6U sizes are specified, as is convection and conduction cooling. This versatility combined with the wide availability of chips, hardware, and software created for the commercial market makes CompactPCI Serial the fastest, most versatile, lowest cost modular high performance open standard for embedded computing on the market today.

With CompactPCI Serial, the CompactPCI architecture moves to serial high-speed interconnects, and more data can be transferred at higher speeds using PCI Express. Additional high speed interfaces, including Ethernet, SATA, and USB are supported.

A typical configuration of one system slot and up to eight peripheral slots does not need switches and bridges. Using the proven 19” mechanics of the IEC 1101 family, proven with CompactPCI and VME, the standard introduces a new rugged additional connector with a signal density of up to 184 pin pairs (on 3U) and transmission frequencies of 12 Gb/s. Hot Swap of boards during operation is supported, as it was with original CompactPCI.

Each system is organized as follows: a System Slot, usually the CPU and often a complete single board computer, provides  8 PCI Express links, 8 SATA/SAS, 8 USB 2.0/3.0 and 8 Ethernet interfaces plus signals for general system management and up to eight peripheral slots.

Each peripheral slot supports 1 PCI Express link, 1 SATA/SAS and 1 USB 2.0/3.0 interface. Each slot can support up to 8 Ethernet interfaces to build a full mesh interconnect without an external switch. All interfaces are accessible at the same time.

The pin assignment of the system and the peripheral slot is congruent. In this way it is possible to plug a system slot board into each peripheral slot to support symmetrical multiprocessing. This is a significant advance over other 3U/6U standards.

Star topologies are supported and each slot is given equal priority: PCI Express, SATA/SAS and USB. All peripheral slots are identical except two that are connected via PCI Express links by 8 lanes.

Ethernet is normally configured as a full mesh. Although alternate topologies are supported. Transmission is based on the proven standards for copper connections up to 10GbaseT to allow configuration of redundant, safety-critical systems. This is important for demanding mil/aero, transportation, security, and many medical applications.

CompactPCI Serial can be combined with existing CompactPCI boards by using a CompactPCI PlusIO system slot card. These hybrid systems offer an ideal migration path from parallel to serial connections.

CompactPCI Serial for Space specifically addresses the extreme environment requirements for outer space.

Revision 2, released on June 16, 2015 provides minor and incremental improvements:

  • New connector, RJ6, is optional and provides an additional 48 pins of rear I/O from the System Slot. The total available I/O pins from the System Slot is now 58.
  • Conduction cooling mechanicals improved (maximum  handle size is now defined)
  • The System Slot can now be located on the right side of the card rack as well as the left side.
  • I2C management bus further defined
  • Location of SATA coupling capacitors clarified

+5 and +12 volts power are normally provided buy an in-rack or external power supply.

Key Benefits and Features

  • Extends parallel PCI bus with serial PCI Express, SATA, Ethernet, and USB, offering higher performance while maintaining mechanical backwards compatibility to CompactPCI. Supported by thousands of available chipsets, chips, and operating systems. 
  • 20x data transfer improvement over PCI Express lanes as compared to CompactPCI. Total data transfer improvement of 80x when Ethernet, SATA, and USB are used. 
  • Supports Hot Swap of boards while a system is operating. This enables the development of mission critical systems. 
  • Convection cooled and conduction cooled modules are defined. 
  • Compliant products are commercially available, including processors, I/O cards, backplanes, card cages, system enclosures, and complete pre-packaged systems. 
  • Wide O/S support 
  • Scalable from a single board to large systems 
  • Hybrid systems allow combination of CompactPCI Serial and CompactPCI peripheral cards, using a CompactPCI PlusIO CPU card in the system slot. 
  • 3U and 6U Eurocard form factors are defined utilizing the popular IEEE 1101.1 and IEEE 1101.10 mechanical standards providing implementation flexibility and widely available off-the-shelf parts.

Family of Specifications

CompactPCI Serial
PICMG# Name Current Revision Date Description

CompactPCI Serial

PICMG# Name Current Revision Date Description
PICMG 2.30


cPCI Serial Space
PICMG# Name Current Revision Date Description

cPCI Serial Space

Target Applications

  • Like CompactPCI, CompactPCI Serial is intended as a general purpose industrial standard for mobile and stationary applications in control and monitoring, data acquisition and instrumentation, simulation and test – from entry-level industrial PCs to complex multiprocessing computer clusters.
  • Because of its extremely high bandwidth, CompactPCI Serial is particularly well suited for high speed / high bandwidth data communication applications.
  • CompactPCI Serial is well suited for industrial markets including robotics, machine control, industrial automation, research, computer telephony and telecommunications, medical equipment and energy sector applications, and ground transportation, avionics and shipbuilding and other mobile markets.
  • Proven Eurocard mechanics, extensive real time O/S support, and conduction cooling capability make CompactPCI Serial an ideal solution for low to moderate cost, modular, and mission critical military, aerospace, and avionics applications.
  • CompactPCI Serial for Space specifically addresses the extreme environment requirements for outer space. It is intended to be used in Space, e.g. on-board satellites as the platform system and the payload controller as well as on Earth for the control systems and ground stations. Regular CompactPCI Serial products can be combined with cPCI Serial for Space products to develop test and simulation systems.



System Requirements

A CompactPCI Serial system usually consists of the following elements:  

  • One or more CPU board(s), which may be complete single board computer(s)
  • A Backplane which distributes signals between boards
  • Card cage for mechanical support of backplane and boards
  • Power Supply: Power supply connections are generally left up to the system implementer
  • I/O cards for application specific I/O
  • Optionally, a chassis to mount everything in.