PXI Specification - PCI eXtensions for Instrumentation ...

1 SpecificationPCI eXtensions for InstrumentationAn Implementation of Revision 20, 1997 Rev. 8/20/97 National Instruments CorporationiiiIMPORTANT INFORMATIONC opyright Copyright 1997 National Instruments Corporation. All rights document is copyrighted by National Instruments Corporation. Permission is granted to reproduce anddistribute this document in its entirety and without PXI Specification is authored and copyrighted by National Instruments Corporation. The intent ofNational Instruments is for the PXI Specification to be an open industry standard supported by a widevariety of vendors and products. Vendors and users who are interested in developing PXI-compatibleproducts or services, as well as parties who are interested in working with National Instruments to furtherpromote PXI as an open industry standard are invited to contact National Instruments for Instruments wants to receive your comments on this Specification . Write to National Instruments,Attn: PXI Specification Committee, 6504 Bridge Point Parkway, Austin, TX Instruments makes no warranty of any kind with regard to this material, including, but not limitedto, the implied warranties of merchantability and fitness for a particular purpose.

2 National Instruments shallnot be liable for errors contained herein or for incidental or consequential damages in connection with thefurnishing, performance, or use of this and CVI are trademarks of National Instruments and company names are trademarks or trade names of their respective companies. National Instruments CorporationRev. 8/20/97ivPXI Specification Revision HistoryThis section is an overview of the revision history of the PXI Specification . Specific individualadditions/modifications to the document between revisions are denoted with diff marks, | , in the rightcolumn of a line of text for which the change , August 20, 1997 This is the first public revision of the PXI 8/20/97 National Instruments CorporationvContents1. Introduction .. Intended Audience and Scope .. Background and Terminology .. Applicable Documents .. 112. PXI Architecture Overview .. Mechanical Architecture System Slot Additional Mechanical Interoperability with CompactPCI.

3 Electrical Architecture Overview .. Peripheral Component Interconnect (PCI) Local System Reference Clock .. Trigger Star System Expansion with PCI-PCI Bridge Software Architecture Common Software Requirements .. Virtual Instrument Software Standards .. Other Software Requirements .. 203. Mechanical Requirements .. CompactPCI Mechanical Requirements .. System Slot Location and Logos and Compatibility Environmental Testing .. Cooling Specifications .. Plug-in Module Requirements .. Chassis Requirements .. Chassis and Module Grounding Requirements and EMI Regulatory Requirements .. Requirements for EMC .. Requirements for Electrical Particular Requirements for Chassis .. 264. Electrical Requirements .. PXI Signal P1/J1: Signals .. P2/J2: Signals .. Signals from CompactPCI 64-Bit Connector 28 System 28 National Instruments CorporationRev. 8/20/97viPeripheral Module .. 29 Backplane .. PXI Reserved and Bused Reserved Signals.

4 30 System 30 Peripheral Slots .. 30 Backplane .. Local Buses .. 30 Peripheral Module .. 31 Backplane .. Reference Clock: Trigger 34 Clock 34 PXI Trigger Protocols .. 34 PXI Asynchronous 34 PXI Synchronous Trigger .. 35 Backplane .. 36 Peripheral or System Module .. Star 38 Backplane .. 39 Peripheral Module .. Electrical Guidelines for Connector Pin Assignments (J1/P1 and J2/P2) .. General Peripheral System Star Trigger Slot .. Chassis Power Supply 475. Software Frameworks and Overview .. Motivation .. Framework Definition .. Windows 95 System Framework .. Introduction .. Overview of the Controller Requirements .. PXI Peripheral Module Requirements .. Windows NT System Framework .. Introduction .. Overview of the Controller Requirements .. PXI Peripheral Module Requirements .. Support for Existing Instrumentation Standards .. System Implementation Issues .. System Configuration and Initialization Files.

5 General .ini File Format .. 55 Rev. 8/20/97 National Instruments PXI System Initialization ( ) File .. Chassis Initialization ( ) Other Chassis Requirements .. 58 FiguresFigure The PXI Architecture .. 10 Figure PXI Peripheral Module Form Factors and 13 Figure Example of a 3U PXI System (Single Bus Segment) .. 14 Figure PXI and CompactPCI Interoperability .. 15 Figure PXI Local Bus Routing .. 17 Figure PXI Trigger Architecture for Two Bus Segments .. 19 Figure Example of PXI Slot Designations for a Chassis .. 22 Figure PXI 23 Figure Star Trigger Slot 23 Figure Cooling Airflow Direction in a PXI 24 Figure PXI Asynchronous Trigger Timing .. 35 Figure PXI Synchronous Trigger 35 Figure PXI Trigger Bus Termination .. 36 TablesTable Bus 32 Table Asynchronous Trigger Timing 35 Table Synchronous Trigger 36 Table Specifications .. 37 Table Resistor Values .. 38 Table A, High Current Driver, AC 38 Table Trigger 39 Table System Signal Groups.

6 41 Table Peripheral Slot Pinout .. 42 Table System Slot 44 Table Star Trigger Slot Pinout .. 46 Table 5 V Backplane Power Requirements and 47 Table V Backplane Power Requirements and 47 Table Environments Supported by PXI Modules underWindows 95 .. 51 Table Environments Supported by PXI Modules underWindows 53 Table Line 56 Rev. 8/20/97 National Instruments Corporation91. IntroductionThis section describes the primary objectives and scope of the PCI eXtensions forInstrumentation (PXI) Specification . It also defines the intended audience and listsrelevant terminology and ObjectivesPXI was created in response to the needs of a variety of Instrumentation andautomation users who require ever increasing performance, functionality, andreliability from compact rugged systems that are easy to integrate and use. Existingindustry standards are leveraged by PXI to benefit from high component availabilityat lower costs. Most importantly, by maintaining software compatibility withindustry-standard personal computers, PXI allows industrial customers to use thesame software tools and environments with which they are leverages the electrical features defined by the widely adopted PeripheralComponent Interconnect (PCI) Specification .

7 It also leverages the CompactPCI formfactor, which combines the PCI electrical Specification with rugged Eurocardmechanical packaging and high-performance connectors. This combination allowsCompactPCI and PXI systems to have up to seven peripheral slots versus four in adesktop PCI system. Systems with more expansion slots can be built by usingmultiple bus segments with industry-standard PCI-PCI bridges. For example, a13-slot PXI system can be built using a single PCI-PCI bridge. The PXI specificationadds electrical features that meet the high-performance requirements ofinstrumentation applications by providing triggering, local buses, and system clockcapabilities. PXI also offers two-way interoperability with CompactPCI implementing desktop PCI in a rugged form factor, PXI systems can leverage thelarge base of existing industry-standard software. Desktop PC users have access todifferent levels of software, from operating systems to low-level device drivers tohigh-level instrument drivers to complete graphical APIs.

8 All of these software levelscan be used in PXI systems. PXI defines software frameworks (for MicrosoftWindows NT and Windows 95) for complete systems and requires appropriatedevice driver software for all PXI peripheral modules to ease system , PXI implements the Virtual Instrument Software Architecture (VISA).VISA is used to locate and communicate with serial, VXI, and GPIB peripheralmodules. PXI extends VISA beyond these interfaces to allow for the location andcontrol of PXI peripheral modules. This extension preserves the model forinstrumentation software that has been adopted by the Instrumentation result is a very powerful software commonality that spans PXI, CompactPCI,desktop PCI, VXI, GPIB, and other Instrumentation diagram in Figure summarizes the scope of the PXI Specification bydepicting its mechanical, electrical, and software architectures. National Instruments CorporationRev. 8/20/9710 PXI: PCI eXtensions for InstrumentationMechanicalArchitectureEle ctricalArchitecturePCI andCompactPCI32/64 BitTransfers33 MHzInstrumentationFunctionsSoftwareArchi tectureStar TriggerReference ClockLocal BusTrigger BusCompactPCIEuroCardPackaging8 SlotsIECC onnectorsPXI AdditionsEnv.

9 TestingCoolingDefined SystemSlot LocationOperatingSystemsWindows 95 DriverSoftwareWindows NTLanguage APIG raphical APIVISAD river RequiredFigure The PXI Intended Audience and ScopeThis Specification is organized with a top-down approach whereby generaldescriptions precede the more detailed specifications found deeper in the structure is intended to serve the needs of a variety of audiences from productdevelopers to system integrators to end-users. Product developers may want tobecome familiar with all portions of this Specification while end users may beinterested in only the feature set description and perhaps the summaries of how thesefeatures are implemented. The goal of this Specification is to serve as the centralsource of information relevant to all users and providers of PXI compatible first section of this Specification describes the features that PXI systems canoffer and how these features can be applied to Instrumentation . The subsequentsections cover the mechanical, electrical, and software requirements specific toimplementing PXI Background and TerminologyThis section defines the acronyms and key words that are referred to throughout thisspecification.

10 This Specification uses the following acronyms:API Application Programming InterfaceEurocard European Packaging Specifications (IEC 60297, IEEE ,IEEE , IEEE )GPIB General Purpose Interface Bus, IEEE 488 ISA Industry Standard Architecture; desktop PC adapter board specificationPCI Peripheral Component Interconnect; electrical Specification defined byPCISIGPCISIG PCI Special Interest GroupRev. 8/20/97 National Instruments Corporation11 PICMG PCI Industrial Computer Manufacturers GroupPXI PCI eXtensions for InstrumentationVISA Virtual Instrument Software ArchitectureVITA VMEbus International Trade AssociationVME Versa Module Europe; VMEbus Specification governed by the VSOVPP VXIplug&play SpecificationVSO VITA Standards OrganizationVXI VME eXtensions for InstrumentationThis Specification uses several key words, which are defined as follows:RULE: Rules SHALL be followed to ensure compatibility. A rule is characterizedby the use of the words SHALL and SHALL : Recommendations consist of advice to implementers thatwill affect the usability of the final module.