Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus expansion or extension
Reexamination Certificate
1998-08-24
2002-02-26
Beausoliel, Robert (Department: 2181)
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus expansion or extension
C710S300000, C710S301000
Reexamination Certificate
active
06351786
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to Versa-Module European (VME) Extensions for Instrumentation (VXI) based systems and products, and in particular, to an apparatus and method for configuring a VXI product plug-in to increase product component density, to an apparatus and method for facilitating the insertion and removal of VXI product carriers into and out of a standard VXI chassis, to an apparatus and method for facilitating the interfacing of new VXI products with a controller of VXI backplane systems, to an apparatus and method for providing an internal bus for selectively coupling VXI product modules, to a method and apparatus for providing an emergency reset mechanism to protect VXI product modules individually or together from potentially hazardous conditions, and to a method and apparatus for providing electromagnetic shielding between VXI product modules.
BACKGROUND OF THE INVENTION
The VXI bus is a standard computer interface bus that originated in Europe, but has been widely accepted around the World. Its primary use has been in the testing and diagnostic field. For instance, it has been used for testing and troubleshooting of automobile components, medical devices such as pacemakers, computer-based systems, and microprocessor integrated circuits. Because of their testing and diagnostic capabilities, VXI bus systems typically comprise a plurality of switching modules. These switching modules connect to a unit-under-test (UUT) for testing and diagnostic purposes. A computer controller interfaces with the VXI backplane system to operate the switch modules in accordance with a testing and diagnostic strategy.
The VXI standard includes numerous specification requirements. These specifications include, for example, chassis size and configuration requirements, power requirements, cooling requirements, backplane protocol requirements, and connector requirements, to name a few. Typically, designers of VXI products must adhere strictly to the required specifications of the VXI backplane system. Of particular interest to the invention is the VXI chassis slot configuration requirements.
FIG. 1
illustrates a simplified representation of the front face of a standard VXI chassis
100
of a VXI based system that is used in the prior art. The standard VXI chassis
100
includes a plurality of standard size slots
102
for respectively receiving therein VXI product plug-in
104
that connect to a VXI backplane bus situated at the back of the chassis (not shown in FIG.
1
).
FIG. 1
illustrates a representative sample of two (2) adjacent slots
102
for housing therein two adjacent VXI product plug-ins
104
. A computer (not shown) can communicate with the VXI product plug-ins
104
by way of the VXI backplane bus through the use of a standard connector
106
located on an adapter module
107
typically positioned within the left-most slot of the chassis
100
. The VXI product plug-ins
104
each include a housing
108
that is sized and dimensioned to slide into respective slots
102
. A module card
110
is contained within each of the housings
108
for performing particular programmable functions. These modules may perform many types of operations, but for the purpose of this application, switch modules will serve to illustrate the invention.
As previously discussed, there are standard size and configuration specifications for the VXI chassis
100
. One of the specifications include slot width and length requirements. Thus, designers of VXI products typically design a plug-in so that it is sized and dimensioned to slide into one of these standardized slots. Accordingly, a VXI product designer is somewhat restricted as to the available area for implementing the desired function(s) for the VXI product plug-in. This typically limits the number of components that can be incorporated into a plug-in. If the products are programmable switching networks, the slot size requirements may limit the number of switches that can be incorporated into a VXI product plug-in.
FIG. 2
illustrates a block diagram of a prior art VXI based system
120
including a pair of VXI switching product plug-ins
130
and
132
positioned within respective VXI chassis slots (not shown in
FIG. 2
) and connected to a VXI backplane bus
142
. The VXI switching plug-ins
130
and
132
include respective carrier housings
134
and
136
(represented by a dashed box) that houses respective pairs of switch cards
138
and
140
. The switching cards
138
and
140
include respective connectors situated at the back side of the carriers in a manner that when the plug-ins are slid into corresponding slots of the VXI chassis, the connectors make operational contact with corresponding connectors on the VXI backplane bus
142
. As it is typical of a VXI bus configuration, it includes lines for supplying power, lines for providing VXI signals, and non-designated lines for custom usage by a designer. The non-designated lines of a VXI backplane bus
142
are typically referred to as the local bus, and will be abbreviated herein as “LBUS.”
Each of the prior art switch module cards
138
and
140
include a plurality of functional circuitry. For instance, they include respective address selector switches and associated circuitry so that the switch modules are separately identified. They also each include a VXI signal decoding circuit for interpreting the commands received from the LBUS. In addition, they each include a differential driver receiver, which is required for receiving the signals from the LBUS. The local bus LBUS comprises a plurality of non-connected segments which may be connected respectively to each of the switching modules. The switching modules each include LBUS Jumper switches in order to cascade or daisy-chain the switching modules. In the diagram shown in
FIG. 2
, the LBUS jumper switches when set connects LBUS IN to LBUS OUT. Each switching module includes a switching bank, typically made of an array of relays and associated interfacing circuitry.
At least one of the switch modules incorporated into the VXI based system
120
should include a controller circuit, such as controller circuit
144
present in switch module
138
. The controller circuit receives the commands or VXI bus signals from the VXI backplane bus
142
, and decodes these signals in order to issue address and data information for all of the modules connected to the LBUS. The address and data information issued by the controller
144
are directly applied to the switch module
138
card that incorporates the controller, or indirectly to the other modules, such as module
140
, through the LBUS, which may be cascaded or daisy-chained as previously discussed. If all the modules are cascaded in the VXI based system, every module will receive the address and data information issued by the controller, and the addressed module or modules will respond accordingly.
Referring now to both
FIGS. 1 and 2
, the prior art VXI based system does not utilize the available slot area of the VXI chassis
100
in the most efficient manner. For instance, each adjacent pair of plug-ins in the system has an unavailable or wasted region
112
between adjacent plug-ins
104
(shown much larger than it really is for the sake of viewing). In addition, there is substantial unnecessary redundancy in each of the switching cards
138
and
140
by the inclusion in each of the cards an address range switch, VXI signal decoding circuit, a differential driver receiver, a power filtering circuit, and LBUS jumper switches, which would not be duplicated if the modules were in one integral package. With this unnecessary redundancy, existing prior art switch modules are limited to switching banks of approximately 160 switching relays. Thus, a total of about 320 switching relays can be accommodated by two adjacent slots
102
. Currently, there is a demand for more relays within that space.
Thus, there is a need to reconfigure the existing design of the prior art VXI based system to reduce the amount of wasted space and unnecessary circuit redundancy so that a hig
Elmore Timothy D.
Knox, II Allan
Masters Daniel C.
Stockwell Michael L.
Talbert Joseph R.
Beausoliel Robert
Newton William A.
Racal Instruments Inc.
Vo Tim
LandOfFree
VXI backplane system improvements and methods does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with VXI backplane system improvements and methods, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and VXI backplane system improvements and methods will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2964929