PXI Bus Description, cPCI for Instrumentation

Compact PCI for Instrumentation Bus

Compact Peripheral Component Interface
PXI Bus

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PXI Description

PXI or CompactPCI (cPCI) for Instrumentation is derived from the cPCI interface bus.
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. The PCI spec defines the Electrical requirements for the interface. No bus terminations are specified, the bus relies on signal reflection to achieve level threshold.

The first version of the PCI bus ran at 33MHz with a 32 bit bus (133MBps), then added 64 bits at 33MHz (266MBps).
The current PCI version runs at 66MHz with a 64 bit bus (532Mbps).

The PCI bus operates either synchronously or asynchronously with the "Mother Board" bus rate. While operating asynchronously the bus will operate at any frequency from 66MHz down to (and including) 0Hz. Flow control is added to allow the bus to operate with slower devices on the bus, allowing the bus to operate at their speed. PCI is an unterminated bus, the signals relay on signal reflections to attain their final value. The PCI specification has been port-ed to a number of other form factors.
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. PXI adds additional signals and chassis requirements just like VXI adds to VME. Unlike VXI, PXI does not require that the card be enclosed in a metal shield.

PXI adds a number of additional signal over the cPCI bus, these signal include:
PXI_CLK10: 10MHz system reference clock
PXI_TRIG[0:7}: Trigger Bus ...
PXI_STAR[0:12]: Star Trigger Bus ..

The newest version of PXI is called PXI Express [PXIe] and combines the PCI Express, cPCI, and PXI standards into a new backplane standard. The specification will retain the form factor described in the cPCI standard, the EMI standards from the PXI standard and adopt the low signal count of the PCIe standard. Software remains compatible with the change from PCI and PCIe, so the movement from PXI to PXIe should also be software independent. The PXIe specification was released in 2005. Refer to the PCIe page for maximum transfer rates.

{PXI Bus Index}

PXI and Compact PCI Standards Info

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

Compact PCI Industrial Computer Manufacturers Group {PICMG} .. IEEE {Institute of Electrical and Electronic Engineers, Inc.}

PXI Specification PCI eXtensions for Instruments Version 1.0, 1997
PXI Specification PCI eXtensions for Instruments Revision 2.0, 2000
An Implementation of CompactPCI

Card dimensions [size] / Form Factor

J1 for either the 3U or 6U form factor is used to provide 32-bit PCI signals.
J2 for either the 3U or 6U form factor is used to provide 64-bit PCI signals and some PXI features.
J3 on the 6U form factor is reserved under the PXI specification.
J4 on the 6U form factor is reserved under the PXI specification.
J5 on the 6U form factor is reserved under the PXI specification Rev 1.0, opened in Rev 2.0.

{PXI Bus Index}

Compact PCI Bus Pin-Out

The PXI bus uses the same pinout as the CompactPCI bus. However there are some additional signals.
The P2 connector adds a number of PXI specific signals, not defined in the cPCI specification.
In addition the system slot contains PXI signals not found on the peripheral slot P2 connector.

PXI P1/J1 Pinout {2mm style} {Common Slot}

PXI P2/J2 Pinout {2mm style} {System Slot}
PXI P2/J2 Pinout {2mm style} {Peripheral-Slot}

The Signal Assignments change from revision 1.0 to revision 2.0 to comply with changes in PICMG 2.0 R3.0

{PXI Bus Index}

PXI Interface IC Manufacturers

Using the same specification as PCI, PXI and cPCI may use the same IC's as the PCI bus specification.
The PCI bus doesn't use Glue logic, being developed as a single chip interface bus. So signal chip solutions or ASIC parts are the only PCI chips listed below.
PCI is a CMOS bus, with no current flowing in the static state. The +5 volt interface uses standard TTL switching levels V_IH = 2v, V_OH = 2.4v. The +3.3 volt interface uses V_IH = 1.65v, V_OH = 2.97v

Integrated Circuit [IC] manufacturers are listed on the PCI Bus page.
The PCI bus uses the same interface drive levels as cPCI and PXI, all the chips are interchangeable and compatible. So there is no need to re-list the manufacturers on this page.

IC Manufacturers{All other types}

{PXI Bus Index}

PXI and cPCI Bus Connector Manufacturers (2mm)

The PXI bus uses 2mm 'Hard Metric'; IEC 1076-4-101, a number of different pin arrangements. 2mm connector manufacturers are listed on the cPCI page.
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:

Type A Connectors; 110 pins, Keyed (J1/J4),([25 rows x 5 columns] - [3 rows x 5 columns of Key])
Type B Connectors; 110 pins (J2/J5), [22 x 5]
Type B Connectors; 95 pins (J3), [19 x 5]. This is also used as P0 with VME64
Type C Connectors; 55 pins [11 x 5]
Type AB Connectors; 95, 110, or 125 pins

There are other types:
Type L Connectors; # contact cavities to accept power insert contacts
Type M Connectors; # contact cavities to accept power insert contacts/with half the connector having normal pins

PXI board formats and connector locations

PXI Euro-Card Form Factor & Connector Locations

Note that the P1/J1 & P2/J2 connectors carrier the PCI isgnals, the others are dedicated to PXI.
PXI connector manufacturers are listed on the cPCI page. Both the cPCI bus and PXI bus use the same connectors.

PXI and Compact PCI Chassis Manufacturers (2mm)

The PXI chassis, or CompactPCI [cPCI] Chassis will be between 1 and 8 slots (the maximum). Either PXI or cPCI chassis will have one controller slot and up to 7 peripheral slots.
The System slot must be at the left end of the PCI segment. 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. In general cPCI and PXI cards may be interchangeable in either type chassis.

PXI, cPCI for Instrumentation uses the same chassis as cPCI. 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.

{PXI Bus Index}

PXI and Compact PCI 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

CompactPCI [cPCI] cards may be either 3U {100mm x 160mm} or 6U {233 x 160mm).
The boards should be keyed to indicate either 5V or 3.3v operation.
3U card will use J1 and may use J2, 6U cards shall use J1 and may use J2 to J5.
J1 is used for 32 bit PCI, J2 is used for 64 bit PCI, J3 to J5 are used for user definable signals.

cPCI Board vendors

ADLINK Technology Inc. {3U PXI System Controller, Intel Pentium based, IEEE488 GPIB Interface, PXI SDRAM, Multi-function DAQ, Analog Output DAQ, SPDT Relay Module}

Geotest Marvin Test Systems, Inc. {Embedded & Remote Controllers, Digital I/O, Switching, Measurement & Stimulus, Power Supplies}

Pickering {PXI Instruments, Switch Modules, Utility Modules}

Sundance Multiprocessor Technology Ltd
{cPCI 3U Carrier with 1 module site; PXI compatible}

Site Navigation: Engineering Home > Electrical Buses > Backplane Buses > PXI Bus.

{PXI Bus Index}


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