CompactPCI Express Bus

Compact Peripheral Component Interface Express
cPCIe Bus

[cPCIe Description] [cPCIe Interface ICs]
[cPCIe Connectors] [cPCIe PinOut] [OnLine Standards]
[cPCIe COTS Cards] [cPCIe Chassis] [cPCIe Backplanes] [PCIe page]

CompactPCI Express Description

The newest version in the cPCI form factor is called cPCIe and trades in the PCI bus for the PCIe bus, but remains in the same board form factor.
CompactPCI Express defines the connector, electrical, and mechanical requirements of 3U/6U System Boards, Peripheral Boards, Switch Boards, and Backplanes in the same cPCI form factor.
CompactPCI Express is also called CPCIe, cPCIe, or CompactPCIe.
PCI Express [PCIe] resides on a 3U x 160mm form factor or 6U form factor in a Compact PCI [cPCI] environment.
The PCI Express 16x and 8x lanes are routed on the P1 and P2 connectors, all other connectors are unused for additional I/O.
See the CompactPCI, or PCI Express listing for additional information.

cPCI [Compact Peripheral Component Interface] is electrically identical to the PCI specification, except it uses the Euro (VME) card 3U/6U format with 2mm connectors.
The cPCI bus uses 8, 16, 32, or 64 bit transfers at up to 264MBps. 64 bit PCI transfers may be used in either 3U or 6U size cards. 6U boards contain additional pins for user defined I/O.
3U card dimensions are 100mm x 160mm x 1.6mm thick, 6U card dimensions are 233.35mm x 160mm x 1.6mm thick.

Most board formats are migrating to the PCIe interface for electrical signaling.
Some formats keep the PCI bus for legacy applications when room allows, otherwise the boards become PCIe only.
Of course any time a board specification take on PCIe, that only applies to the signals and electrical specifications.
Addition features of cPCI include; live insertion support (Hot-Swap), supports two independent buses on the backplane (on different connectors), and soon Infiniband, Ethernet, and Star Fabric support (Switched Fabric based systems).

PXI defines cPCI for Instrumentation adding additional enhancements, with the same form factor as cPCI, using the PCI bus.
PXI Express adopts the PCIe interface into the PXI standard [which had been PCI over cPCI].
PXI Express uses both PXI connectors and new connectors for PXI Express.

CompactPCI Express Online Standards Info

EXP.0 CompactPCI Express
PICMG 2.0 Rev 3.0 CompactPCI Core Specification; See also the PCI Page
PICMG 2.1 Rev2.0 CompactPCI Hot Swap
PICMG 2.2 Rev1.0 VME64x on CompactPCI [VME64x bus on the P4/P5 connectors]
PICMG 2.3 Rev1.0 PMC on CompactPCI
PICMG 2.4 Rev1.0 IP on CompactPCI
PICMG 2.5 Rev1.0 CompactPCI Computer Telephony
PICMG 2.7 Rev1.0 6U CompactPCI Dual System Slot Specification
PICMG 2.9 Rev1.0 CompactPCI System Management
PICMG 2.10 Rev1.0 Keying of CompactPCI Boards and Backplanes
PICMG 2.11 Rev1.0 CompactPCI Power Interface
PICMG 2.12 Rev2.0 Hot Swap Infrastructure Interface
PICMG 2.14 Rev1.0 CompactPCI Multicomputing Specification
PICMG 2.15 Rev1.0 PCI Telecom Mezzanine/Carrier Card [H.110 [TDM bus] Computer Telephony]
PICMG 2.16 Rev1.0 CompactPCI Packet Switching Backplane Specification [cPSB] (GigaBridge, Ethernet)
PICMG 2.17 Rev1.0 CompactPCI StarFabric Specification
PICMG 2.20 Rev1.0 CompactPCI Serial Mesh Backplane Specification
PXI Rev 1.0 PXI; PCI eXtensions for Instrumentation
PXI Express PCI Express Extensions for Instrumentation

PICMG {Compact PCI Industrial Computer Manufacturers Group}, []

Card dimensions [size] / Form Factor

cPCI Express Card size description, and Board Dimensions

{cPCIe Bus Index}

Compact PCI Express Bus Pin-Out

Pinouts for the other connectors found on a 6U card are user defined.
While the pinout for a 3U card is fully defined by the links above. The 3U size card use the J1, P2, P3, P4 connectors.

{cPCIe Bus Index}

CompactPCI Express Bus Interface IC Manufacturers

Compact PCIe is the PCI Express bus on a different board form factor, so;
Integrated Circuit [IC] manufacturers are listed on the PCIe Bus page.
The electrical interface is the same, only the board size is changed.
Of course mechanically the connector style and their pin outs change as well.

IC Manufacturers {All other types}

{cPCIe Bus Index}

cPCI Bus Connector Manufacturers (2mm)

cPCI uses 2mm 'Hard Metric'; IEC 1076-4-101, a number of different pin arrangements. Normally the outside Ground rows (which are compression pins) 'Z' and 'F' are not counted as pins. OEM pin numbering may be by cPCI or in accordance with IEC 61076-4-101 (which is reversed). The term "Hard Metric" only means that metric dimensions are preferred ~ with-out regard to inches.

cPCI 2mm connectors mating distances [12.50mm] matches the 96 pin DIN 41612 connectors used with other EuroCard packaging [IEC 273 or IEEE 1101, 1101.10], like VMEbus. FutureBus connectors, which also use 2mm style has a mating distance of 10mm, and is not compatible with cPCI connectors.

The types below are counting signal pins (not the ground rows), as indicated on many data sheets:

cPCIe Connector Location
CompactPCIe Euro-Card Form Factor

The card side connector is Male (Right-Angle), the back plane side is Female (Straight).

Connector Vendors;


Delphi Connection Systems






Hirose Electric

ITT Industries

Meritec {2mm cPCI backplane cable assemblies, off the shelf product and customizable products.}


OUPIIN America Inc.

Positronic Industries {Power Module Connectors}

Tyco Electronics

Comm Con Connectors Inc. has a nice page showing the different types.

Compact PCI Chassis Manufacturers (2mm)

CompactPCI [cPCI] Chassis will be between 1 and 8 slots (the maximum). Printed Wiring Boards [PWB] are spaced on 0.8 inch centers.
The chassis may accept 3U cards, or 3U and 6U cards. The chassis may have a separate card cage to handle the 3U cards.

The chassis shall provide a +5volt, +/- 12volt and a 3.3volt supply @ maximum ripple 50mV. I believe the Telcom version provides 48 volts as the system power.
The backplane is passive. The bus requires one card acting as the systems controller residing at either end of the back-plane (chassis), termed the System Slot. The remaining cards (slots) are termed the Peripheral Slots.

PXI, cPCI for Instrumentation uses the same chassis. cPCI and PXI Chassis manufacturers

In cPCI, the system slot may reside in any slot of the back plane with the other 7 slots as peripheral cards. In PXI, the left most slot is the system slot followed on the right by 7 peripheral slots. In addition, 3 other slots, with do not contain back plane connectors may reside to the left of the system slot. These additional 3 slots provide expansion (wider card) for the system card.

{cPCIe Bus Index}

Compact PCI Express COTs Card Manufacturers

CompactPCI [cPCI] uses the Euro Format [dimensions], see figure above.
IEEE 1101.1 Base Document for Mechanics
IEEE 1101.10 Mechanics for VME Boards and Subracks
IEEE 1101.11 Mechanics for Rear Transition Modules

cPCIe Card manufacturers and vendors, for a list of board and backplanes.

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Modified 6/13/15
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