National Instruments Corporation

Bob Mitchell

Hugo A Andrade

Samson L DeKey

Jogen Pathak

Todd Brower

Brian Keith Odom

Kevin L Schultz

Abhay Shah

Robert Wayne Hormuth

Craig M Conway

Glen Sescila

B Keith Odom

Ross Sabolcik

Pratik Mukundray Mehta

Robert W Canik

Dan Mondrik

David Henry Dorr

Abhay S Shah

Timothy Lynn Moor

Nigel D Waites

A Wide Area Serial PCI system for connecting peripheral devices to a computer. The WASP system includes a host computer system connected through a serial bus to a remote device. The serial bus can range from several meters to several kilometers or more. The host computer system includes a CPU and memory, and also includes a first Peripheral Component Interconnect (PCI) bus, also referred to as the local PCI bus. A primary bridge according to the present invention is coupled to the first PCI bus. The primary bridge includes PCI interface circuitry for interfacing to the first PCI bus. The remote device is located remotely from the computer system and comprises a second or remote PCI bus and one or more peripheral devices coupled to the second PCI bus. The remote device also includes a secondary bridge coupled to the second PCI bus. The secondary bridge includes PCI interface circuitry for interfacing to the second PCI bus. The serial bus is coupled between the primary bridge and the secondary bridge. Each of the primary bridge and secondary bridge include parallel/serial transceivers for converting parallel data generated on the first PCI bus and second PCI bus, respectively, to serial data for transmission on the serial bus and for converting serial data received from the serial bus to parallel data for generation on the first PCI bus and second PCI bus, respectively. The primary bridge and the secondary bridge collectively implement a PCI&mdash;PCI bridge register set.

System and method for connecting peripheral buses through a serial bus

System and method for coupling peripheral buses through a serial bus using a split bridge implementation

A VXI chassis which has user selectable or configurable slot 0 locations. The VXI chassis includes a personality module interface coupled to the VXI backplane comprised in the chassis. The personality module interface or slot is adapted to receive a personality module. The personality module can be inserted into the personality module interface or slot in one of a plurality of orientations. Based on the orientation of the inserted personality module, the personality module is operable to selectively route signals on the backplane to enable one of a plurality of locations to operate as the slot 0 location. In the preferred embodiment, the VXI chassis can house a plurality of C size and/or B size VXI/VME cards, and the VXI chassis is configurable between different slot 0 locations for different size cards, i.e., between either a C-size or B-size slot 0 controller. Thus the VXI chassis of the present invention provides an innovative solution for using both C-size VXI and B-size VXI/VME resources in a single system. The selection of a C-size or B-size slot 0 controller provides increased options to the user and reduces system costs.

Chassis which includes configurable slot 0 locations

A system and method for increasing the performance of read cycles in instrumentation systems having multiple interconnected buses by converting the read cycles into write cycles and taking advantage of the write posting and FIFO buffering capabilities of the bus interface logic between each of the interconnected buses. When a requestor device desires to initiate a read cycle of memory situated on the same or a different bus, the requestor device first creates a data transfer packet containing information about the desired data. The requestor device then generates a write cycle to DMA logic situated near the memory desired to be read. The DMA logic uses the 32 bit address provided from the requestor device, to obtain information about the transfer and then initiates DMA write cycles to perform the desired transfer. Since each bus interface bridge includes write posting capability, the write operation can be performed much more efficiently than a read operation. The write posting capability requires that only (one) bus be tied up at a given time, and thus write cycles perform much more efficiently. The present invention is also capable of operating in either direction.

System and method for converting read cycles into write cycles for

A system and method for controlling a computer-based instrumentation system which provides simplified application development and improved performance for instrumentation systems. The present invention provides a system including a software architecture which defines the control and management of an instrumentation system. The present invention includes a base object class, an object manager, session and resource classes, and one or more resource templates. The instrumentation system of the present invention provides a plurality of instrument control resources which are used as building blocks to create instrument drivers and higher level applications. The present invention also uses object oriented technology which allows device resources to be easily combined to create higher level applications. The present invention is independent of I/O interface type, operating system, and programming language while also providing a common look and feel and consistent API to the user. The present invention includes novel methods for access control, event handling, resource management, and resource addressing, among others.

System and method for controlling an instrumentation system

A method and apparatus for controlling instrumentation systems and for providing a user with the capability to develop instrument drivers and application software for controlling instrumentation systems. The present invention provides a system including a software architecture which defines the control and management of an instrumentation system. The method of the present invention utilizes a device resource independence approach whereby the individual capabilities of devices are broken down into a plurality of objects called resources and these resources are then used to develop instrument drivers or instrument control applications. The method of the present invention also uses object oriented technology which allows device resources to be easily combined to create higher level applications. The present invention is independent of I/O interface type, operating system, and programming language while also providing a common look and feel and consistent API to the user. The present invention includes novel methods for access control, event handling, resource management, and resource addressing, among others.

Method and apparatus for controlling an instrumentation system

A system and method for improved handling of events in an instrumentation system which provides numerous features and advantages over prior art methods. The present invention provides simplified application development and improved performance for instrumentation systems. The instrumentation system of the present invention provides event queueing, event handling, and suspend handling features, thus providing the user or developer with greater freedom in designing his test and measurement or process control application. The present invention includes a single operation referred to as viEnableEvent which is used for enabling events of all event types, and a single operation for installing handlers for all event types, referred to as viInstallHandlr. The operation viEnableEvent includes one or more parameters which can be specified as a filter to qualify the types of events desired to be received at the time of the event occurrence. This provides the user with greater control over which events are specified to be received. The present invention further includes an auto-acknowledge capability which enables a resource to automatically provide an acknowledge to an instrument generating an interrupt. An auto-enable feature is included for resources within the system which provides that if there are multiple sessions, the first session for which events are enabled enables the respective event receiving hardware, and the hardware remains enabled until the last session has been disabled. The present invention further provides several different mechanisms for generating interrupts within the system. For example, a user application can cause a resource to signal a session that an event has occurred, thus enabling the user application to create events within the system. Alternatively, an event can be generated internally to a resource and constructed within a resource. Further, an asynchronous notification method is provided whereby an event could be generated by a first resource and trapped by a second resource.

System and method for handling events in an instrumentation system

A system and method for developing instrument drivers and applications in a computer-based instrumentation system. The present invention provides simplified application development and improved performance for instrumentation systems. The instrumentation system of the present invention provides a plurality of instrument control resources which are used as building blocks to create instrument drivers and higher level applications. The present invention also uses object oriented technology which allows device resources to be easily combined to create higher level applications. The present invention is independent of I/O interface type, operating system, and programming language while also providing a common look and feel and consistent API to the user. A developer creates a resource in the VISA system by first determining if the desired resource can inherit from a currently existing resource. If the resource desired to be created can inherit from an existing resource, then the developer creates session and resource classes from the base classes that are being inherited from. If the developer determines that a resource does not currently exist from which the resource can inherit, then the developer inherits from the base session and resource classes provided in a VISA system. After either of the above steps, the developer creates an interface description language for the resource and session classes that have been created for the resource. The interface description language describes the interface for the session and resource classes created for the session. The developer then creates the code which supplements and/or overwrites the code in the existing resource that was inherited from. The code is created to provide operations, attributes, and events for the new resource. Once the code has been created and debugged, then a resource has been created for controlling the particular instrument. In a similar manner, various other types of instrument drivers in higher level instrumentation applications can be created by inheriting from existing resources.

System and method for creating resources in an instrumentation system

An instrumentation system according to the present invention which automatically demultiplexes multiplexed data received from multiple analog channels. The system includes a plurality N of analog channels that are multiplexed into an A/D converter. The A/D converter in turn supplies the multiplexed or interleaved digital data to an external computer where the data is stored in memory. The external computer includes direct memory access (DMA) demultiplexing logic according to the present invention which automatically reads the multiplexed data and rewrites the multiplexed data into a non-interleaved or demultiplexed format. Once all the multiplexed digital data has been received and stored in the computer system, the demultiplexing logic of the present invention performs DMA transfers to demultiplex or de-interleave the data into N independent buffers or memory spaces which are no longer interleaved. The DMA multiplexing logic performs a transfer for each analog channel to split the data for each analog channel into separate buffers. The DMA demultiplexing logic performs each transfer by incrementing through addresses of the multiplexed data to transfer only the data corresponding to a respective analog channel. The demultiplexing logic increments by the transfer size and an address sequencing value which is the number of analog channels of data in the multiplexed data. In other words, the DMA demultiplexing logic sequences a multiple N times the transfer size, wherein the multiple N is the number of analog channels of interleaved data received by the computer system.

System and method for demultiplexing data in an instrumentation system

A system and method for performing more efficient hardware context switches in a computer-controlled instrumentation system including a computer system which controls a plurality of instruments. The instrumentation system includes a direct memory access transfer device which performs various data transfers between the computer system and the various instruments. The direct memory access transfer device includes different hardware contexts for different transfers, and the DMA transfer device automatically configures itself to different contexts with minimal CPU involvement. For each process or thread requiring a different DMA transfer device context, the CPU prepares the context information and stores the context in memory. The CPU then provides a request list to the DMA transfer device including interleaved context pointers and data transfer packets. When the DMA transfer device is performing transfers and needs to switch to a new context, the DMA transfer device reads the context from memory and automatically configures itself. Since, the context is stored in memory and hence readily available, the DMA transfer device does not have to interrupt the CPU to receive a new context. Once the CPU has prepared and stored the context information and provided the address of the context information to the DMA transfer device, the DMA transfer device can switch between contexts for transfers corresponding to different processes or threads numerous times without CPU involvement, thus increasing system efficiency.

System and method for performing efficient hardware context switching in

A system and method for enabling applications written for NI-VXI driver level software to operate with a session-based VISA system. The present invention receives driver level function calls from applications developed for the NI-VXI driver level library, opens sessions to the appropriate VISA resources and performs the necessary operations on these resources. This enables a VISA system to operate in conjunction with applications written for the NI-VXI driver level library. When a call to the NI-VXI function InitVXIlibrary is received, the method allocates one or more arrays which are used later for storing session identifiers to sessions created to corresponding VISA resources. When the system later receives a call to a function in the NI-VXI driver level library, the method first determines which VISA resources correspond to this function. The method either opens sessions to these resources or retrieves the session parameters from the respective arrays if sessions have already been created. The method performs one or more operations on the VISA resources to perform the functionality indicated by the function called in the NI-VXI library. In many instances, the method of the present invention is required to invoke multiple VISA operations to perform the desired functions indicated by a call to a single NI-VXI function. When a call to the NI-VXI function CloseVXIlibrary is received, the method closes all sessions to VISA resources.

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Austin, TX, United States of America

Bob Mitchell