User-controllable connectivity engine for electronic design
Contents
1. 18 The computer readable medium of claim 12 wherein one of said operating modes causes said computer system to re assign a first connectivity object a new Net when said first connectivity object is separated from a second connectivity object and said first and second connectivity objects were assigned to the same Net 19 The computer readable medium of claim 12 wherein one of said operating modes causes said computer system to assign an orphaned connectivity object to a new unique Net when said connectivity object is created 20 The computer readable medium of claim 12 wherein one of said operating modes causes said computer system to remove a Net assignment that is currently assigned to one of said connectivity objects when that connectivity object is orphaned UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO 8 584 077 B1 Page I of I APPLICATION NO 13 562173 DATED November 12 2013 INVENTOR S Arbind Kumar et al It is certified that error appears in the above identified patent and that said Letters Patent is hereby corrected as shown below On Title page Item 56 under Other Publications in column 2 line 1 delete NioPluse and insert NioPulse therefor Signed and Sealed this Twenty fifth Day of February 2014 Job le Michelle K Lee Deputy Director of the United States Patent and Trademark Office2. and the Flight Wires finally disappear when the last connectivity object is inserted such that the connectivity object touches both objects on the sides of the remaining gap The present invention also gives the user control of Net Overlap Zones Refer now to FIGS 6A 6B which illustrate the generation and removal of a Net Overlap Zone FIG 6A shows a portion of a layout having two Nets that are separate from one another These are the two Nets shown in FIG 3 prior to the Net Overlap Zone being created by moving one Branch to a position that overlaps the other Branch FIG 6B shows these Nets after the user has moved one of the Nets such that the two Nets now overlap In this case a Net Overlap Zone 43 is automatically generated If the user selects Net Overlap Zone 43 a dialog box 44 appears which asks if the user would like to merge the two Nets into a single Net In this example trace 32 is on Net N_ 3 and trace 23 ison Net N_ 5 The user is given the choice of a name for the merged Net from the names of the existing Nets If the user chooses to merge the Nets the unused Net name is eliminated and the selected Net definition is enlarged to include the connection objects on the Net that was merged into the remaining Net The Net Overlap Zone is then removed from the layout In one aspect of the invention the behavior of the layout mode when two connectivity objects are brought together or disconnected can be configured as an automati
3. Branch indicator is found that connectivity object is assigned a Branch indicator that has not yet been used for any connectivity object as shown at 73 Next all connectivity objects that touch that connectivity US 8 584 077 B1 7 object either directly or through a connectivity object that has been assigned the Branch indicator are visited and given the same Branch identifier as shown at 74 The connectivity objects in the database are then searched for a connectivity object without a Branch indicator When no connectivity object with an unassigned Branch field is left all of the Branches are defined The algorithm then proceeds to process each Branch Refer now to FIG 8 which illustrates the processing of each Branch In the first step all connectivity objects on the current Branch that have Net assignments that can be changed are marked as shown at 81 First all connectivity objects on the Branch are marked as being unvisited Next the connec tivity objects on the Branch that are capable of changing their Net assignments are marked This will be all connectivity objects on the Branch except connectivity objects which are already on a Net forced by the user or on an implicitly forced Net by virtue of being on the Join operating mode Next the Net assignments from orphaned connectivity objects that can be removed from a Net are removed as shown at 82 A connectivity object is not removed from a Net ifeither the Branch has
4. a forced Net or any ofthe connectivity objects on the Branch is not marked with the Eliminate isolation mode discussed above If a connectivity object is removed from a Net the Net is deleted if the Net is empty and the Branch processing is finished for this step Next the Branch connectivity is updated for connectivity objects having their operating mode set as shown at 83 This is a four pass procedure In the first pass connectivity objects that are touching but cannot change their Nets are identified as shown at 83 The connectivity objects are processed one at a time to reset the unvisited marking for connectivity objects that are either on a forced Net or an implicitly forced Net When a such a connectivity object is found the connectivity object is marked as visited Then all connectivity objects on the same Net that touch the connectivity object in question either directly or through another connectivity object on the Net are marked as being incapable of having their Net assign ment changed Finally all connectivity objects on the Branch are again reset to the unvisited state In the second pass Net assignments to connectivity objects which are touching directly or indirectly and which can change their Net assignments are assigned new Net assign ments if they are connected to a connectivity object that cannot have its Net assignment changed This is accom plished by finding each connectivity object that is marked unv
5. a second Net that is different from the first Net based on the second Net In another aspect ofthe invention one of the operating modes causes the com puter system to re assign a first connectivity object a new Net when the first connectivity object is separated from a second connectivity object and the first and second connectivity objects were assigned to the same Net In another aspect ofthe invention one of the operating modes causes the computer system to assign an orphaned connectivity object to a new unique Net when the connectivity object is created In another aspect of the present invention one of the operating modes causes the computer system to remove a Net assignment that is currently assigned to a connectivity object when it is orphaned In another aspect of the invention the operating mode associated with one of said connectivity objects can be altered after the connectivity object has been created In another aspect of the invention the operating mode associated with one of said connectivity objects is provided when the connec tivity object is created BRIEF DESCRIPTION OF THE DRAWINGS FIGS 1 illustrate the classes of objects FIG 2A illustrates a portion of a layout having a resistor and a capacitor FIG 2B illustrates the Nets included in the portion of the layout shown in FIG 2A FIG 3 illustrates a Net Overlap Zone FIG 4 shows a portion of FIG 2A in which the user has deleted trace 23 and moved Pin 2
6. assigning a Net assignment for that connectivity object based on said operating modes and Nets assigned to other connectivity objects that are connected to that connectivity object 13 The computer readable medium of claim 12 wherein defining said plurality of connectivity objects comprises providing a list of objects in a user selectable format including connectivity objects that are placed in said display area and included in said layout and selecting a connectivity object from said list of objects based on user input 14 The computer readable medium of claim 12 wherein one of said operating modes prevents said computer from automatically assigning a Net for that connectivity object 15 The computer readable medium of claim 12 wherein one of said operating modes causes said computer system to assign a Net to a first connectivity object that is not already on a Net to a Net determined by a Net assignment to a second connectivity object that touches said first connectivity object 16 The computer readable medium of claim 15 wherein said computer displays a Net Overlap Zone if said first and second connectivity objects are assigned different Nets 17 The computer readable medium of claim 12 wherein one of said operating modes causes said computer system to assign a Net to a first connectivity object on a first Net that touches a second connectivity object on a second Net that is different from said first Net based on said second Net
7. nor a Net Overlap Zone In the operating mode automatic changes to the connectivity objects when the touching objects are dragged apart or when an object starts touching another are not per formed Dragging apart two connectivity objects on the same Net creates a Flight Wire Touching two connectivity objects on separate Nets creates a Net Overlap Zone The user then operates onthe Flight Wire or Net Overlap Zones manually as discussed above Refer now to FIG 9 which illustrates a computer system that is suitable for practicing the present invention The present invention can be practiced on a data processing sys tem 60 that includes computer 64 a graphical user interface 61 for displaying the layout drawing and a data input inter face for receiving input from a user The user typically inputs commands to the data processing system via a keyboard 62 and a pointing device 63 The data processing system main tains a database that includes a table specifying each connec tivity object in the layout and a Net identifier for that object When the user creates a connectivity object the connec tivity object will be represented in a database in which space is allocated for a Net identifier for that object In one aspect of the invention three isolation modes are provided In the Cre ate operating mode the data processing system automati cally assigns a unique Net identification to an orphaned con nectivity object when t
8. 1 2003 Nakatsu et al 716 120 6 857 110 2 2005 Ruppetal 716 136 7 016 794 B2 3 2006 Schultz 702 64 7 353 482 B2 4 2008 Murakawa 7 707 495 B2 4 2010 Hosotsubo 715 243 8 046 730 B1 10 2011 Ferguson et al 8 136 076 2 3 2012 Bachina et al 716 126 2009 0319975 12 2009 Huynhetal 716 10 2010 0100862 A1 4 2010 716 13 2013 0125078 A1 5 2013 Bosshart 716 126 OTHER PUBLICATIONS NioPluse User Manual Version 2 0 1 Draft Apr 26 2012 NioPulse 273 pages Microwave Office Training Feb 15 2008 Advancing the Wireless Revolution 15 pages cited by examiner Primary Examiner Phallaka Kik 57 method for operating computer system to generate layout of a device and computer readable medium contain ing instructions that cause a computer system to carry out that method are disclosed The computer system has a display that includes a display area The computer system provides a list of objects and creates user selected objects from the list for inclusion in the display area The computer assigns one of a plurality of operating modes for each connectivity object in the layout The computer generates Net assignment for each connectivity object that is not forced to have specific Net assignment and for which automatic assignment
9. 12 United States Patent Kumar et al US008584077B1 US 8 584 077 B1 Nov 12 2013 10 Patent No 45 Date of Patent 54 75 73 21 22 51 52 58 56 USER CONTROLLABLE CONNECTIVITY ENGINE FOR ELECTRONIC DESIGN AUTOMATION TOOLS Inventors Arbind Kumar New Delhi IN John Robert Lefebvre II Atlanta GA US Krishna Kumar Banka Haryana IN Peter Niday Genoa NV US Assignee Agilent Technologies Inc Santa Clara CA US Notice Subject to any disclaimer the term of this patent is extended or adjusted under 35 U S C 154 b by 0 days Appl No 13 562 173 Filed Jul 30 2012 Int CI GOGF 17 50 U S CI CPG 2006 01 G06F 17 5077 2013 01 GO6F 17 5022 2013 01 GO6F 17 505 2013 01 GO6F 17 5072 2013 01 GOGF 17 5081 2013 01 716 139 716 102 716 118 716 126 716 138 703 14 Field of Classification Search GOGF 17 5022 GOGF 17 505 GO6F 17 5072 GOGF 17 5077 GO6F 17 5081 USPC 716 139 102 118 126 138 703 14 See application file for complete search history References Cited U S PATENT DOCUMENTS 5 414 809 A 6 240 541 5 1995 Hogan et al 715 765 5 2001 Yasuda et al 716 112 YES 80 MORE BRANCHES TO PROCESS MARK ALL CONNECTIVITY OBJECTS ON CURRENT BRANCH THAT ARE CAPABLE OF CHANGING NET ASSIGNMENTS 6 513 147 Bl
10. 7 such that it no longer is connected to Pin 28 FIG 5 illustrates the removal of a Flight Wire by filling a gap in the Net FIGS 6A 6B illustrate the generation and removal ofa Net Overlap Zone FIG 7 is a flow chart of the procedure for identifying the Branches in the layout FIG 8 illustrates the processing of each Branch FIG 9 illustrates a computer system that is suitable for practicing the present invention FIG 10 illustrates the display that is used to input data that defines the layout of a device DETAILED DESCRIPTION At the layout level a circuit can be viewed as a plurality of objects that are connected together In a layout design system US 8 584 077 B1 3 according to the present invention the user builds a layout by selecting objects from a menu and placing instances of those objects in the display area The user can change the size and shapes of the objects and connect the objects to provide the layout of the final device These objects can be viewed as belonging to five classes Refer to FIGS LA C which illustrate the classes of objects The first class consists of shapes such as rectangles circles polygons etc that are layers of conductor as shown in FIG 1 Referring to FIG 1B the second class consists of wires and traces Wire 11 has endpoints 12 and 13 that are connected by a line that has no thickness Trace 16 differs from a wire in that trace 16 has a thickness as well as end points 14
11. OHfHO AJLIALLOdNNOO HHL OL QH LOHNNOO LVHL SLOH HO ALIALLOHNNOO TIY ANIA HONV IH MAN V OL ALIALLO3NNOO LNYATAEND JHL NDISSV YOLVOIGNI HONV UE GYNDISSVNA NV LOdfHO ALIAILJENNOD SI 12 SUOLVIIANI 9 TIV LIS HU LUYVIS US 8 584 077 B1 Sheet 10 of 12 Nov 12 2013 U S Patent 8 FYNDII ES LAS SHGON DNILV3IHdO DNIAVH NO SLOH 8O ALIALLOHNNOO AOA S LNHIWNDISSV LAN HONVHO SLOALdO ALIAILOANNOO GYNVHdYO INO SLAN HAOINGSEOLCOV SINANNDISSV LAN DNIDNVHO d1dVdVO TAV LVHL HONVYH LNTAANO NO ANOA SILDdfgo ALIALLOANNOO YAYN SHA JQO NOLLV IOSI HHL DNIAVH SLOdrado 6SSHOO ld OL SHHONV 3IH TAON ALIAILOANOD GYNVHdUO SINANNDISSV LAN 1 442 Be 8 U S Patent Nov 12 2013 Sheet 11 of 12 US 8 584 077 62 DISPLAY COMPUTER KEYBOARD 60 a z D e US 8 584 077 B1 Sheet 12 of 12 Nov 12 2013 U S Patent I 6 OT TANIA S dvdL JAYN d IdH TAIM NODA TOd YDVUL Nid S LOHfHO US 8 584 077 B1 1 USER CONTROLLABLE CONNECTIVITY ENGINE FOR ELECTRONIC DESIGN AUTOMATION TOOLS BACKGROUND Electronic design automation EDA tools are used to facilitate the design and testing of complex electronic cir cuitry These systems provide tools for inpu
12. alculated and added to the layout view to indicate amissing link Similarly a Flight Wire 38 is added to show the missing connection between Pin 27 and Pin 28 In the present invention the user has two options for removing a Flight Wire First the user can delete the Flight Wire by selecting the Flight Wire and pressing the delete key The present invention then moves the connectivity objects that were connected by the Flight Wire to different Nets and hence the unrouted Net condition is removed and the Flight Wire is no longer generated to signal an unrouted Net The operation of moving one of the Branches that was connected by the Flight Wire to a new Net is referred to as splitting the Net in the present invention When the user splits the Net the present invention assigns one of the two Branches to a new Net The identifier for this Net is either provided automati cally by the program or the user can provide an identifier for the new Net Second the user can remove the Flight Wire by physically connecting the Net Branches with one or more connectivity objects such as traces or by moving one of the connectivity objects so that the gap is filled Refer now to FIG 5 which illustrates the removal of a Flight Wire by filling a gap in the Net In this example Pin 27 is reconnected to Pin 28 by inserting a trace 41 to fill the gap created by moving Pin 27 When the gap is eliminated by filling the gap the underlying Net retains its identity
13. and 15 Referring to FIG 1C the third class consists of compo nents such as resistors capacitors inductors microstrip lines transmission lines etc component has two or more con nection points and processes an input signal to produce an output signal resistor is shown at 19 in FIG 1 with its connection points shown at 17 and 18 The fourth class consists of Pins Pins are connection points on objects such as the connection points on resistor 19 discussed above Pin can also be separate object denoted by an arrow such as the arrow as discussed below This type of Pin provides connection point to circuitry that is external to the circuit in the layout The fifth class of objects are helper objects such as text labels rulers etc Helper objects assist the designer while creating a layout and are not part of the manufactured circuit or component For example a ruler will help the designer place two components at a specified spacing The manner in which the present invention provides its advantages can be more easily understood in terms of a logi cal construct referred to as a Net The first second and fourth classes of objects are referred to as connectivity objects in the following discussion as these objects have functions analogous to wires in that they connect the other objects connected thereto to the same signal A number of connec tivity objects that are connected together to form a signal path ar
14. c mode or a manual mode In the automatic mode three operations are carried out without user intervention when two connectivity objects start or stop touching In the Join operating mode when a connectivity object not on a Net touches another connectivity object on a Net the system of the present inven tion automatically puts the connectivity object that was not on a Net on the existing Net If both of the connectivity objects are on separate Nets touching them creates a Net Overlap Zone In the Merge operating mode when a connectivity object on a first Net touches another connectivity object on a sepa 20 25 30 35 40 45 50 55 65 6 rate second Net the first Net is automatically merged with the second Net by assignment of the connectivity objects on the first Net to the second Net If one of the connectivity objects is not on a Net that connectivity object is automatically placed on the same Net as the other connectivity object s Therefore Join can be viewed as a sub set of Merge When two connectivity objects that have been merged are touching dragging them apart creates a Flight Wire In the WYSIWYG operating mode when two connec tivity objects which are touching are dragged apart they Split In this case each of the split objects is placed on a unique Net WYSIWYG can be viewed as a super set with both Merge and Split and neither creates a Flight Wire
15. cess In another system Flight Wires are introduced for this pur pose The Flight Wires are automatically removed when the connection is restored Similarly when two objects in the layout are moved such that they overlap an overlap region is formed that is indicated by specific pattern on the display that is automatically inserted by the layout engine These overlaps signal that the objects need to be joined to form a single conductor Again the generation of these constructs is not under the control of the user In schematic driven modes of design the software attempts to maintain synchronization between the layout and the sche matic In complex layouts the number ofthese constructs and their locations can inhibit the designer s ability to efficiently input the design In addition the models used for maintaining connectivity during the layout process vary depending on the particular EDA product and hence users of one system can have difficulty when they are forced to work in a different system SUMMARY The present invention includes a method for operating a computer system to generate a layout of a device and a com puter readable medium containing instructions that cause a computer system to carry out that method The computer system has a display that includes a display area A plurality of connectivity objects are defined for the device each con nectivity object being part ofthe device An operating mode is defined for ea
16. ch connectivity object in the layout The com puter generates a Net assignment for each connectivity object that is not forced to have a specific Net assignment and for which automatic assignment of a Net is allowed The com 20 25 30 35 40 45 50 55 60 65 2 puter generated assignment depends on the operating mode associated with that connectivity object The operating mode of at least one of the connectivity objects can be altered by input from a user of said computer system In one aspect of the invention defining the plurality of connectivity objects includes providing a list of objects in a user selectable format including connectivity objects that may be placed in said display area and included in said layout and selecting a connectivity object from the list based on user input In one aspect of the invention one of the modes prevents the computer from automatically assigning a Net for one of the connectivity objects In another aspect of the invention one of the operating modes causes the computer system to assign a Net to a first connectivity object that is not on already on a Net to a Net determined by a Net assignment to a second connectivity object that touches the first connectivity object In a still further aspect of the present invention one of the operating modes causes the computer system to assign a Net to a first connectivity object on a first Net that touches a second connectivity object on
17. e referred to as a A Net is analogous to a trace on a printed circuit board and represents an electrical path in a circuit Any two points on a Net are shorted together electri cally and hence have the same signal In the present invention each connectivity object has a Net assignment with the possible exception of orphaned shapes discussed below The assignment can be made automatically by the present invention or forced by the user When a change is made to the layout new Net assignments are made to reflect the change For example if a connectivity object is intro duced into the layout that fills a gap between two objects that are on different Nets the Net assignments of the connectivity objects on one of the previously defined Nets must be changed to reflect the new connectivity of the layout A connectivity object that is not touching any other con nectivity object is referred to as an orphaned connectivity object in the following discussion A connectivity object can start out in an orphaned state because it is placed on the layout at a position such that it is not in contact with any other connectivity object A connectivity object can become orphaned when it is moved from a position in which it was touching another connectivity object to a position in which it no longer touches other connectivity objects Orphan shapes do not have Net assignments when they are initially created Refer now to FIG 10 which illustrates
18. ect with the WYSIW YG operating mode which is either on forced or an implicitly forced Net mark the connectivity object as visited Visit all connectivity objects that are touching this connectivity object either directly or indirectly through another connectivity object and that can change their Net assignments Put these connectivity objects on the same Net as the identified connectivity object and mark these connectivity objects as being incapable of changing their Nets In one aspect of the invention the iden tifiers for Nets that lost connectivity objects in this procedure are recorded If one or more Nets are eliminated in this pro cess the eliminated Net names are placed in recycle pool so that the same net names can be reused when required When all of the Branches have been processed as shown at 80 Nets are created for orphaned connectivity objects having the Create isolation mode set as shown at 85 The computer goes through the list of connectivity objects to find any remaining connectivity objects with the Create isolation mode set and that are not ona Net For each such connectivity object a new Net is created Then any connectivity objects that can still have their Nets changed and which are connected directly or indirectly to the connectivity object in question are assigned to the new Net The above described embodiments of the present inven tion have been layout driven That is the user enters the layout wi
19. hat connectivity object is created by the user In the Eliminate operating mode the orphaned connectivity object is removed from the current Net during the connectivity processing algorithm discussed below In the None mode an orphaned connectivity object neither cre ates nor eliminates a Net assignment associated with that connectivity object The user can also force a connectivity object to be on a Net defined by the user The database also allocates space in the entry for each object to store a mode for that object The mode identifies one of the modes discussed above The connectivity algo rithm uses these modes to alter how the connectivity objects are assigned to the Net after a change in the layout has occurred The database also allocates space for a Branch identifier for each connectivity object In one aspect of the invention each time the layout changes the data processing system recalculates the Nets Flight Wires and Net Overlap Zones that are to be displayed Refer now to FIG 7 which is a flow chart of the procedure for identifying the Branches in the layout At the beginning ofthe process all ofthe Branch indications are reset as shown at 71 Next a determination is made as to whether there is a con nectivity objected with an unassigned Branch indicator as shown at 72 If no connectivity object with an unassigned Branch indicator is found the process is complete If a con nectivity object with an unassigned
20. isited and which is either on a forced or an implicitly forced Net For each such identified connectivity object the connectivity object is marked as being visited For each con nectivity object that touches the identified connectivity object either directly or through another connectivity object and which can change its Net assignment put that connectivity object on the same Net as the identified connectivity object and mark that connectivity object as being incapable of changing its Net assignment In the third pass Net assignments for connectivity objects that have the Merge operating mode set and have not been visited in the preceding passes are made For each unvisited connectivity object with the Merge operating mode which is either on a forced or an implicitly forced Net mark the connectivity object as visited Visit all connectivity objects that are touching this connectivity object either directly or indirectly through another connectivity object and that can change their Net assignments Put these connectivity objects on the same Net as the identified connectivity object and mark these connectivity objects as being incapable of chang ing their Nets _ 0 an 5 20 40 45 50 55 65 8 Inthe fourth pass Net assignments for connectivity objects that have the WYSIWYG operating mode set and have not been visited in the preceding passes are made For each unvis ited connectivity obj
21. n an orphaned connectivity object to a new unique Net when said connec tivity object is created 9 The method of claim 1 wherein one of said operating modes causes said computer system to remove a Net assign ment that is currently assigned to one of said connectivity objects when that connectivity object is orphaned 10 The method of claim 1 wherein said operating mode associated with one of said connectivity objects is altered after said connectivity object has been created 11 The method of claim 1 wherein said operating mode associated with one of said connectivity objects is provided when said connectivity object is created 5 20 25 30 35 40 45 50 55 10 12 A computer readable medium that includes instruc tions that cause a computer having a display area to generate a layout of a device by defining a plurality of connectivity objects each connec tivity object being part of said device receiving one of a plurality of operating modes for each connectivity object in said layout said operating mode determining how a Net is automatically assigned to that connectivity object said operating mode of at least one of said connectivity objects being alterable by input from a user of said computer system and for each connectivity object that is not forced to have a specific Net assignment and for which automatic assign ment ofa Net is allowed by said operating mode received for that connectivity object
22. of a Net is allowed The computer generated assignment depends on the operating mode associated with that connectivity object The operating mode of at least one of the connectivity objects can be altered by input from a user of said computer system ABSTRACT 20 Claims 12 Drawing Sheets 85 CREATE NET ASSIGNMENTS FOR ORPHANED CONECTIVITY OBJECTS HAVING THE CREATE ISOLATION MODE AUTO REMOVE NETS FROM ORPHANED CONNECTIVITY OBJECTS 82 CHANGE ASSIGNMENTS FOR CONNECTIVITY OBJECTS ON CURRENT BRANCH HA VING OPERATING MODES SET 83 U S Patent Nov 12 2013 Sheet I of 12 US 8 584 077 2 D 22 5 22 5 e S 13 11 12 U S Patent Nov 12 2013 Sheet 2 of 12 N SN KR gt lt U S Patent Nov 12 2013 Sheet 3 of 12 U S Patent Nov 12 2013 Sheet 4 of 12 US 8 584 077 B1 U S Patent Nov 12 2013 Sheet 5 of 12 V FYNDIY US 8 584 077 B1 U S Patent W N G NNN s US 8 584 077 B1 U S Patent V9 FYNDI4 H9 dSI 1DI4 US 8 584 077 B1 oo w 3 P 2 p 70590993 7 54 273 en N R m gt Z Nu HIAVN ESN SHA aS Nu DAWN TSN STA SLIN HO3ETIA U S Patent US 8 584 077 B1 Sheet 9 of 12 Nov 12 2013 U S Patent L TANDIJ vL EL HNOd CL I
23. on different Nets will be discussed below Refer now to FIG 3 which illustrates a Net Overlap Zone Here Net 31 which includes trace 32 overlaps trace 23 which is part of Net 29 In one aspect of the present invention the Net Overlap Zone is shown in the layout view if the connec tivity objects that are touching are not on the same Net In this example the Net Overlap Zone is shown at 34 The combi nation of traces 23 and 32 is an example of a Branch in which all the connectivity objects are not on the same Net In the present invention Flight Wires show incomplete or unrouted Nets A Flight Wire is defined to be a line that appears in display area 91 and indicates a missing connection between two connectivity objects A Net that has multiple Net Branches because all of its connectivity objects are not touch ing is referred to as an unrouted Net These connectivity objects are on the same Net but not physically connected The lack of connection can result from a connectivity object being removed The Flight Wires show the missing connec tions by bridging the region that is not connected Refer to US 8 584 077 B1 5 FIG 4 FIG 4 shows a portion of FIG 2A in which the user has deleted trace 23 and moved Pin 27 such that it no longer is connected to Pin 28 As a result the remaining connectivity objects of the Net i e Pin 25 and Pin 26 are no longer touching and hence Net 29 is now an unrouted Net Flight Wire 37 is c
24. rminals on a component have different signals and hence are on different Nets Refer now to FIG 2A which illustrates a portion of a layout having a resistor and a capacitor Capacitor 21 is con nected to resistor 22 by trace 23 which is connected to a Pin 25 on capacitor 21 and a Pin 26 on resistor 22 The other Pin on resistor 22 Pin 28 is connected to a Pin 27 shown as an arrow Pin 27 connects the resistor to an external signal or power source Refer now to FIG 2B which illustrates the Nets included in the portion of the layout shown in FIG 2A Pin 25 trace 23 and Pin 26 are ona first Net 29 The objects that are on this Net are indicated by the thicker boundary line in FIG 2B Pin 27 and Pin 28 are on a second Net that is different from the first Net Two connectivity objects that overlap one another are said to be touching The objects can be on the same layer or different layers that bind Two layers are said to bind if the layers can be interconnected electrically For example two metal layers ina semiconductor can be connected by a via that runs vertically between the metal layers Branch is defined to be a group of connectivity objects that are touching but may be on different Nets A Net Branch is defined to bea group of connectivity objects which are touching and are on the same Net Referring to FIG 2B Net 29 is a Net Branch An example of a Branch in which the connectivity objects that are touching are
25. rovide other embodiments of the present invention In addition various modifications to the present invention will become apparent from the foregoing description and accompanying drawings Accordingly the present invention is to be limited solely by the scope of the following claims What is claimed is 1 A method of operating a computer system having a display area to provide a layout for an electronic device said method comprising defining a plurality of connectivity objects within said computer system each connectivity object being part of said electronic device US 8 584 077 B1 9 receiving one of a plurality of operating modes for each connectivity object in said layout said operating mode determining how a Net is automatically assigned to that connectivity object said operating mode of at least one of said connectivity objects being alterable by input from a user of said computer system and for each connectivity object that is not forced to have a specific Net assignment and for which automatic assign ment ofa Net is allowed by said operating mode received for that connectivity object causing said computer sys tem to make a Net assignment for that connectivity object based on said operating modes and Nets assigned to other connectivity objects that are connected to that connectivity object 2 The method of claim 1 wherein defining said plurality of connectivity objects comprises providing a list of objects in a u
26. ser selectable format including connectivity objects that are placed in said display area and included in said layout and selecting a connectivity object from said list of objects based on user input 3 The method of claim 1 wherein one of said operating modes prevents said computer from automatically assigning a Net for that connectivity object 4 The method of claim 1 wherein one of said operating modes causes said computer system to assign a Net to a first connectivity object that is not on already on a Net to a Net determined by a Net assignment to a second connectivity object that touches said first connectivity object 5 The method of claim 4 wherein said computer displays a Net Overlap Zone if said first and second connectivity objects are assigned different Nets 6 The method of claim 1 wherein one of said operating modes causes said computer system to assign a Net to a first connectivity object on a first Net that touches a second con nectivity object on a second Net that is different from said first Net based on said second Net 7 The method of claim 1 wherein one of said operating modes causes said computer system to re assign a first con nectivity object a new Net when said first connectivity object is separated from a second connectivity object and said first and second connectivity objects were assigned to the same Net 8 The method of claim 1 wherein one of said operating modes causes said computer system to assig
27. the display that is used to input data that defines the layout of a device Display 90 includes two windows 91 and 92 Window 91 displays the current layout with the objects that have been defined so far in 20 40 45 50 65 4 the process Window 92 displays a menu of possible objects that can be added to the display In practice the user indicates an item from window 92 and drags that item onto the display window 91 The user can modify the object by changing the object shape location or other parameters particular to the object in question Shape 95 is an example of an orphaned connectivity object The user can specify a particular object using a cursor 93 and predetermined operation such as double clicking amouse button associated with the cursor A window 94 that provides the parameters associated with the object is then displayed In one aspect of the invention the user can edit the data shown in window 94 and hence change the parameters associated with the corresponding object It should be noted that the display format shown in FIG 10 is one exemplary display format Other formats will be appar ent from the following discussion For example the details of the menu that specify the available objects can be varied to make more efficient use of display space Components are connected through various connectivity objects Since a component transforms inputs thereto into outputs that are different from the inputs the te
28. thout reference to a schematic that has already been entered into the design system and which defines the connectivity between the various components of the device being designed A schematic diagram can then be created from the completed layout view of the device However the present invention can be utilized in a sche matic driven system In this case Flight Wires are generated when a Net defined on the schematic is broken either because it has not been fully inputted in the layout mode by connecting all the connectivity objects corresponding to that Net or because components in the layout mode have been moved or eliminated In the schematic driven embodiments one or more of the connectivity objects are forced onto Nets that are defined in the schematic The present invention includes any computer readable medium that causes a computer to execute instructions that carry out the above described method for operating a com puter system For the purposes of this application the term computer readable medium is defined to be any medium that constitutes patentable subject matter under 35 U S C 101 Examples of such media are non transient media such as memory devices The above described embodiments of the present inven tion have been provided to illustrate various aspects of the invention However it is to be understood that different aspects of the present invention that are shown in different specific embodiments can be combined to p
29. tting both the schematic drawing for a circuit and the layout of the actual physical components on a semiconductor substrate or printed circuit board For example a transmission line in the sche matic is represented in the layout by two physical conductors having defined widths and lengths that overlap one another on two different layers in the layout The designer can alter the physical dimensions and placement of the components in the layout view during the layout process In addition the sizes and other parameters of the layout components can be opti mizedby the EDA tools during testing and optimization ofthe circuit parameters The schematic view and circuit layout view are typically linked such that the components of the circuit in the layout view remain connected during the editing of the layout view in the layout tools As the user moves objects in the layout view connectivity can be broken Connectivity can also be broken when the user moves components connected by a trace in the layout view such that the conductor now includes a break The layout software attempts to maintain connectiv ity in the layout view by providing constructs or actual wires that are introduced to complete the connection that was bro ken In one system the layout engine adds a physical wire to the layout that reconnects the two separated components These wires can give rise to production errors if the wires are not manually removed at the end of the layout pro
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