Abstract:
The coupling apparatus couples two circuit cards to fit into a larger chassis. A coupling element can connect two similar sized circuit cards or two different sized circuit cards together by coupling the first circuit card and the second circuit card to effectively form a combined circuit card of a larger size. The larger size may allow for more features, may make it easier to dissipate heat, may make the circuit cards easier to shield, and/or may allow for the use of larger and less expensive components on the circuit cards.

Description:
FIELD OF THE INVENTION 
   The present invention relates to an adapter for coupling two cards of one size to create a combined card of a second size, and more specifically to create a combined card in a CompactPCI/PXI form factor. 
   DESCRIPTION OF THE RELATED ART 
   An instrument is a device which collects data or information from an environment or unit under test and displays this information to a user. An instrument may also perform various data analysis and data processing on acquired data prior to displaying the data to the user. Examples of various types of instruments include oscilloscopes, digital multimeters, pressure sensors, etc., and the types of information which might be collected by respective instruments include voltage, resistance, distance, velocity, pressure, frequency of oscillation, humidity or temperature, among others. 
   The various hardware interface options currently available for instrumentation systems can be categorized into various types, including IEEE 488-controlled instruments (GPIB instruments), Virtual Machine Environment (VME) Extensions for Instrumentation (VXI) bus instruments, Peripheral Component Interconnect (PCI) Extensions for Instrumentation (PXI) bus instruments, plug-in data acquisition (DAQ) boards, and RS-232-controlled (serial) instruments, among others. 
   The PXI bus is a platform for instrumentation systems that was introduced in 1997. PXI combines the high-speed PCI bus with integrated timing and triggering designed specifically for measurement and automation applications to deliver significant performance improvements over older architectures. PXI is built on the modular and scalable CompactPCI specification and the high-speed PCI bus architecture. As a result, PXI products maintain complete interoperability with CompactPCI, offering superior mechanical integrity, easy systems integration, and more expansion slots than desktop computers. 
     FIG. 1  (Related Art) Exemplary Chassis 
     FIG. 1  illustrates an exemplary chassis of either VXI, VME, CompactPCI, or PXI type. Cards  102 A,  102 B, and  102 C are designed to physically connect with the chassis backplane (not shown). The chassis  100  comprises a housing which is configured to define a plurality of slots. The backplane is comprised in the housing and is adapted for transmitting electrical signals. Cards  102 A,  102 B, and  102 C can be of either 3U or 6U size, such as described below with reference to  FIG. 2 . 
     FIG. 2  (Related Art) Various Card Formats 
     FIG. 2  illustrates different card formats as defined by the IEEE 1101.10, CompactPCI, and PXI specifications. The IEEE 1101.10, CompactPCI, and PXI specifications define two card sizes, referred to as 3U and 6U, and two chassis sizes, referred to as 3U and 6U, designed to accept 3U and 6U cards, respectively. The IEEE 1101.10, CompactPCI, and PXI specification define 6U card size to be more than twice as tall as the 3U card size. 
   Since there are different chassis sizes and different card sizes, it would be advantageous to allow different sized cards to fit into different sized chassis. For example, related art such as Front Panel Adapter, PN# 3687098 and PN# 3687471 from Rittal may allow users to connect two 3U cards into a single 6U slot in a 6U chassis. However, Rittal and related solutions may require a pre-defined set of mounting holes on the cards  102 A,  102 B, and  102 C in order to use the adapter. The pre-defined holes may not be universal to all CompactPCI cards  102 A,  102 B, and  102 C, thus making the adapter difficult to utilize properly. Other related art includes solutions for a 6U chassis with a pre-defined number of 3U slots, such as products from Adlink, Ziatech, and Diversified Technologies. 
   SUMMARY OF THE INVENTION 
   In one embodiment, a first module and a second module may be combined using a coupling element to provide a larger circuit area. For example, the first module and the second module may have similar circuit areas and coupling the first module to the second module may provide double the circuit area as provided by either the first module or the second module. In another embodiment, the first module may be larger than the second module. Other module sizes are also contemplated. 
   In one embodiment, the first module may be an adapter card such as, but not limited to a Riser Card with a PCI Express to PCI Bridge. In one embodiment, the PCI Express to PCI Bridge may convert a PCI Express signal to a PCI signal. The first module may also pass along PXI-specific trigger and clocking signals and provide additional depth to interface a Legacy PXI card to a PCI Express backplane. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiment is considered in conjunction with the following drawings, in which: 
       FIG. 1  illustrates a prior art chassis of VXI/VME/CompactPCI/PXI type; 
       FIG. 2  illustrates prior art various card formats; 
       FIG. 3  illustrates an exemplary embodiment of the apparatus, according to one embodiment; and 
       FIG. 4  illustrates another exemplary embodiment of the apparatus, according to one embodiment. 
   

   Although the system and method of the present invention has been described in connection with the preferred embodiment, it is not intended to be limited to the specific form set forth herein, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents, as can be reasonably included within the spirit and scope of the invention as defined by the appended claims. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Incorporation by Reference 
   U.S. Pat. No. 5,995,376 titled “Chassis which includes configurable slot  0  locations” filed May 20, 1997, is hereby incorporated by reference as though fully and completely set forth herein. 
   U.S. Pat. No. 6,198,633 B1 titled “Computer system and enclosure thereof” filed Jul. 17, 1998, is hereby incorporated by reference as though fully and completely set forth herein. 
   FIG.  3 —Exemplary embodiment of the apparatus 
     FIG. 3  illustrates an exemplary embodiment of an apparatus for coupling a first module  300 A to a second module  300 B to form a combined module  360 . For example, the first module  300 A may be an adapter card such as, but not limited to a PXI Riser Card with an incorporated PCI Express to PCI Bridge. For example, the PXI Riser Card may work with the interface described in U.S. patent application Ser. No. 10/014,638 titled “Instrumentation System Including a Backplane Having a Switched Fabric Bus and Instrumentation Lines”, which was filed Oct. 26, 2001, whose inventors are Mark Wetzel, Michel Haddad, Joseph E. Peck, and Christopher A. Clark, and which issued on Dec. 27, 2005 as U.S. Pat. No. 6,981,086, which is hereby incorporated by reference in its entirety as though fully and completely set forth herein. U.S. Pat. No. 6,981,086 discloses a backplane having a switched fabric bus (such as PCI Express) and instrumentation lines. In one embodiment, the adaptor card may have an incorporated PCI to PCI Express Bridge. In yet another embodiment, the adaptor card may have an incorporated PCI Express to PCI-X Bridge. In one embodiment, the PCI Express to PCI Bridge may convert a PCI Express signal to a PCI signal. The first module  300 A may also pass along PXI-specific trigger signals and clocking signals and provide additional depth to interface a Legacy PXI card to a PCI Express backplane. In one embodiment, the PCI Express backplane may use a PCI Express communication protocol. In one embodiment, the backplane may use a PCI communication protocol. A PCI Express interface used with the backplane may have a reduced pin count compared to a PCI interface used wit the backplane. 
   In one embodiment, the second module  300 B may be a Legacy PXI Card. In one embodiment, the second module  300 B may have a front face  310 , while the first module  300 A may have a back face  350 . In one embodiment, the front face  310  may provide an interface between the second module and an external component such as, but not limited to, a peripheral device. The back face  350  may have one or more connectors for coupling to a chassis  100 . The first module  300 A and the second module  300 B each may have a first lateral edge  320 A and  320 B respectively. The first lateral edge  320 A and  320 B may each have a first keep-out region  330 A and  330 B respectively which together may extend at least a portion of the distance from the front face  310  to the back face  350 . 
   The first module  300 A and the second module  300 B may each have a second lateral edge  322 A and  322 B respectively. The second lateral edge  322 A and  322 B may be located opposite to the first lateral edge  320 A and  320 B respectively. The second lateral edge  322 A and  322 B may each have a second keep-out region  332 A and  332 B respectively, which together may extend at least a portion of the distance from the front face  310  to the back face  350 . Also, in one embodiment, the second module  300 B may have at least one injector/ejector lever  315 . The injector/ejector lever  315  may be operable to inject/eject a module  300 A,  300 B, and/or  360  into/out of a chassis  100 . 
   In one embodiment, the apparatus may have one or more coupling elements  375  operable to couple the first module  300 A and the second module  300 B. In one embodiment, the coupling element  375  may be a PXI Connector. A combined module  360  may be formed by coupling the first module  300 A to the second module  300 B. In one embodiment, each of the first module  300 A and the second module  300 B may have a similar size or a different size. The combined size of both the first module  300 A and the second module  300 B may provide a larger circuit area. In one embodiment, the larger circuit area may be provided while maintaining a PCI-Express standard communication protocol. 
   In one embodiment, the combined module  360  may be operable to be inserted into a slot in the chassis  100 . In one embodiment, the chassis  100  may have one or more slots each operable to receive a module  360  with a larger circuit area than a traditional 3U card. 
   FIG.  4 —Exemplary Embodiment of the Apparatus 
     FIG. 4  illustrates an exemplary embodiment of an apparatus for coupling a first extended module  405  to a second module  400  to form a combined module  460 . In one embodiment, the first extended module  405  may be a carrier module with an incorporated PCI Express to PCI Bridge. In one embodiment, the second module  400  may be a Legacy PXI Card. In one embodiment, the second module  400  may have a front face  410 , while the first extended module  405  may have a back face  450 . In one embodiment, the front face  410  may be coupled to both the first extended module  405  and the second module  400 . The back face  450  may have one or more connectors for coupling to a chassis  100 . The first extended module  405  and the second module  400  may each have a first lateral edge  440  and  442  respectively. The first lateral edge  440  may have a first keep-out region  445 , and the second lateral edge  442  may have a first keep-out region (not shown), which together may extend at least a portion of the distance from the front face  410  to the back face  450 . In one embodiment, the first keep-out region  445  may extend between the front face  410  and the back face  450 . 
   The first extended module  405  and the second module  400  may each have a second lateral edge  425  and  422  respectively. The second lateral edges  425  and  422  may each be located opposite to the first lateral edges  440  and  442  respectively. The second lateral edge  425  and  422  may each have a second keep-out region  435  and  432  respectively, which together may extend at least a portion of the distance from the front face  410  to the back face  450 . Also, in one embodiment, the first extended module  405  may comprise at least one injector/ejector lever  415 . The injector/ejector lever  415  may be operable to inject/eject a module  405 ,  400 , and/or  460  into/out of a chassis  100 . 
   In one embodiment, the apparatus may have one or more coupling elements  475  operable to couple the first extended module  405  and the second module  400 . In one embodiment, the coupling element  475  may be a PXI Connector. A combined module  460  may be formed by coupling the first extended module  405  to the second module  400  to provide a greater circuit area. In one embodiment, the combined module  460  may be operable to be inserted into a slot in the chassis  100 . In one embodiment, the chassis  100  may have one or more slots each operable to receive a module  460 . In one embodiment, the first extended module  405  may have a greater height and width than the second module  400 . The first extended module  405  may be used to allow the second module  400  to fit in a larger chassis. The second module  400  may have a height approximately equal to 3U. Other module sizes are also contemplated. 
   Numerous variations and modifications will become apparent to those skilled in art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.