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Layout Autorouter User's Guide

1. Type Select the type of pass that you want the autorouter to perform Heuristics Sweeps through the design in an attempt to route connections using simple wire patterns defined by the router Fanout Routes most SMT pads to through vias The router uses a simple pattern search to locate legal locations inside and then outside the IC In some cases especially on a doubled sided SMT board neither path is clear In that case the router will drop the connection and go on to the next one You can ignore failures during this sweep because the router will connect them later This option is not recommended See the note below Note You should perform fanout on the board prior to autorouting Fanout is best performed using the Fanout Settings dialog box See Fanout on boards with surface mount devices in Chapter 2 in this manual Maze Sweeps through the design attempting different paths to make connections Via Reduce Use the VIARED_H or VIARED_V strategies to run via reduction on the fully routed board In most cases Via Reduce is unnecessary since the router minimizes vias as it progresses through the routing operation Auto DFM Automatically Design for Manufacturer Attempts to straighten tracks and clean up the board You usually do not need to run Auto DFM because the router straightens and cleans up the board on its own Auto CDE Automatically Clear Design Errors Attempts to remove incomplete tracks from the board so that
2. 4 Inthe Layers spreadsheet double click once again on the layer that is now designated as the jumper layer The Edit Layer dialog box displays 5 Choose the Jumper Attributes button The Jumper Lengths dialog box displays 6 Enter the appropriate data then choose the OK button 7 Secure components that must stay in their current position on the board by selecting them and choosing Lock from the pop up menu This locks the components on the board 8 Create route keepouts for all of the components on the jumper layer to keep the jumper vias outside of the components The easiest way to do this is to make a copy of the place outline and define the copy as a route keepout using the Edit Obstacle dialog box Then place the route keepout on the jumper layer See For information on editing and copying obstacles see Editing obstacles and Copying obstacles in Chapter 5 Creating and editing obstacles in the OrCAD Layout User s Guide For information on the footprint editor see Chapter 14 Creating and editing footprints in the OrCAD Layout User s Guide 9 From the File menu choose Load The Load File dialog box displays 10 Select one of the two jumper strategies JUMPER_H SF for horizontal jumpers or JUMPER_V SF for vertical jumpers You should choose the strategy that corresponds to the longer axis of your board horizontal or vertical Choose the Open button 11 Adjust the DRC box to encompass the entire board If this is not po
3. Use free vias Permits the use of free vias for optimal implementation of power and ground fanout If this option is not selected regular vias are used 10 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Fanout Signals Determines whether Layout implements fanout for signals connected to SMD pads A signal is any net that is not enabled on a plane layer Lock after fanout Locks the signal tracks and vias after fanout is complete In general it is best to leave signal tracks unlocked so the autorouter can move them as necessary to finish routing the board Share close vias Permits tracks belonging to the same signal to share a single via Via sharing for signals reduces the number of vias on and therefore the congestion of the board Use free vias Permits the use of free vias for optimal fanout of signals connected to SMD pads If this option is not selected regular vias are used Inside Allows Layout to place fanout vias inside or under the SMD Outside Allows Layout to place fanout vias outside the SMD Maximum Fanout Distance The value you set for this option determines the maximum distance from an SMD pad to a fanout via This distance is the Euclidean distance measured from the center of the SMD pad not the cumulative distance of the associated track segments By default the value for this option is 300 mils Note Layout places vias on grid points only If there is no
4. and Between Pins then choose the OK button The Edit Layer Strategy dialog box 28 Selections l Routing Enabled Layer Cost Low Normal High Primary Direction ECLI r Vert Any Horz Between Pins lt ee oi Free Avoid Help Cancel Layer Cost Determines how expensive it is to route on a given layer For example for an SMT design you may want to avoid the outer layers because that is where the pins are located Layer Cost should generally be set within the range of 40 to 60 except for some special cases For example if you want to avoid routing on a particular layer except when needed set the overall cost of that layer to 90 Generally speaking for through hole boards it is best to set each horizontal and vertical pair of layers to a slightly different overall cost This distributes the buses evenly through the board The default strategies for through hole boards are already set up this way OrCAD Layout Autorouter User s Guide 31 Chapter 3 Using routing strategy files Primary Direction Primary Direction is not set on a scale from 0 to 100 Vertical layers are assigned a value between 0 and 49 and horizontal layers are assigned a value between 51 and 100 The closer the value is to 50 the more freedom the router has to route in any direction on a given layer The closer the value is to 0 the more strictly vertical the layer The closer the value is to 100 the more strictly horizontal
5. 1 Gridded autor uter EE REKE Se GE RR ER Eg Ge ee ee De sa EEN be AD ee seed DEE Ge RE GE DE ea eb Es Eg 1 Sweep technology sis He NR dicted GEK ee ie Ses eke eg ENE ek Ee SKEER Eei EEES 1 Shove technology EE ES ee ee ee Se 1 Interactive routing mode sesse ee e ee ee ee ee Ge Re Re iE Re Re ee Esar 2 Gridless shape based autorouter eee ee se ek Ge ee GR ee AR ee GR Ge Re Ge ee ek Gee ee 2 Chapter 2 Using autorouting and interactive routing sees esse 3 Loading a routing strategy file 0 ees se ee se ee Re GR GR ee SA Ge Re Ge ee GR Gee Re eke ee 5 Routing power and ground on predominantly through hole boards iese sees 6 Fanout on boards with surface mount device iese sesse seke se Ge ee Ge ee GR Ge ee 8 Implementing power and ground fanOut iese se sesse se se ee Gee ek Ge ee eke ee 9 Implementing full board fanout iese ee ee ee ee ee AR Ge Re Re GE Re ER RA 12 Using interactive routing tools 0 sesse ee se ee ke GR GR ee GRA Ge ee Ge Re ek Gee Re eke ee 13 Using shove track mode eis Es Re Aon eN GE doe acne bite austen acai 13 Using auto path route mode ese se se se se ee Ge Re GR Re GR Ge Re GR ee RA Ge ee 14 Pr routing Critical DetS en sinned SEE Ke KEER onsaasdscyocseeschisesenyssssptoesustensspeuotbestesths 15 Autorouting a boards is ts Ete bees EES e gee ese t Re Ve ee ONE Ea ei 16 Disabling power and ground sesse see ee se ee Ge AA Ge Re Gee Re GR Gee Re eke ee 16 Running th
6. Autoroute command 6 autorouting 16 connecting nets to plane layers for boards with through holes 6 SMT boards 8 gridded gridless 7 2 layer parameters 3 passes 26 pre routing critical nets 75 single sided boards 19 spacing parameters 33 sweeps 16 25 B Between Pins 32 Board command 8 9 12 16 C commands Autoroute 16 Board 8 9 12 16 Component amp Convert to Components 20 21 22 Copy 19 Create Reports 18 Design Rule Check 9 17 DRC Route Box 8 Enable lt gt Disable 16 Index Fanout 8 9 12 Fanout Settings 9 12 Jumper 20 21 22 Jumper Settings 20 21 Load 5 20 Lock 15 21 Properties 17 19 Route Settings 73 15 Test Point Settings 17 Component command 8 connecting nets to plane layers 6 Convert to Components command 20 21 22 Copy command 19 Create Reports command 8 creating jumpers for single sided boards 22 critical nets pre routing 15 D Design Rule Check command 9 17 disabling nets for routing 16 DRC Route Box command amp DRC Route Box resizing 27 E editing route layer information 3 route pass information 28 route spacing information 33 route sweep information 25 Enable lt gt Disable command 6 OrCAD Layout Autorouter User s Guide 35 Index F fanout 12 full board 12 power and ground 9 Fanout command 8 9 12 Fanout Settings command 9 2 G H gridded autorouting interactive routing tools 2 s
7. autorouter finds the optimal space for a given track and then moves or shoves other tracks out of the way before routing in that area If a pad or via is blocking the routing path then the autorouter attempts to go around the blockage by routing to a different layer using a via The autorouter also checks to see if there are obstructing tracks that can be rerouted or moved to an entirely different location on the board OrCAD Layout Autorouter User s Guide 1 Chapter 1 Introduction to autorouting Interactive routing tools Though not part of the autorouter itself interactive routing tools complement the gridded autorouter by allowing you to refine an autorouted board Using auto path route mode and shove track mode you can route critical nets and dense boards with minimal effort LL See For information on auto path route mode and shove track mode see Using interactive routing tools in chapter 2 of this manual Gridless shape based autorouter Layout Plus provides a gridless shape based autorouter called SmartRoute Exclusive to Layout Plus SmartRoute has fast routing speeds high completion rates and high router quality LL See For information on SmartRoute see the OrCAD Layout SmartRoute User s Guide 2 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing LQ LQ This chapter explains how to prepare a board for autorouting how to route a board using autorouting a
8. grid point within the maximum distance you specified a via may be placed on a grid point beyond this distance OrCAD Layout Autorouter User s Guide 11 Chapter 2 Using autorouting and interactive routing Implementing full board fanout It is not necessary to implement fanout for all pads that are not connected to power and ground because the router can route pads for which it could not place a fanout via For multilayer SMD boards you should normally let the router determine via locations rather than implement fanout The sheer number of vias created with fanout can block too many channels for the router to work efficiently especially on dense SMD boards However for fine pitch components it is useful to run component fanout since this is typically the only way you can fanout all pins without blocking off one or more pins in the process Before you implement full board fanout ensure that power and ground are disabled for routing and that all other signals are enabled LL See For instructions on enabling signals for routing see Disabling power and ground in this chapter To complete full board fanout 1 From the Options menu choose Fanout Settings The Fanout Settings dialog box displays Deselect the Fanout Power Gnd option Select the Fanout Signals option and your choice of the options under it See the description of the options in this chapter 4 Ifyou want fanout to place vias inside or under SMDs s
9. list of the routing strategy files used with Layout see Appendix A Understanding the files used with Layout in the OrCAD Layout User s Guide For information on loading routing strategy files see Loading a strategy file in Chapter 2 Using autorouting and interactive routing in this manual OrCAD Layout Autorouter User s Guide 23 Chapter 3 Using routing strategy files Editing strategy files The strategy files are based on information in four sets of data sweep parameters pass parameters layer parameters and spacing parameters You can view these four data sets in spreadsheet form by using the spreadsheet toolbar button By editing the parameters in these spreadsheets you can create new strategy files SF and edit the existing strategy files that drive autorouting The spreadsheets are listed below Route Sweep Using the Route Sweep spreadsheet you can edit the existing route sweep parameters Route Pass During autorouting the router makes a specified number of cycles or sweeps through the current working area component DRC Box or board During the sweeps the autorouter uses different routing mechanisms in the attempt to route the connections Using the Route Pass spreadsheet you can enable and disable sweeps and sweep passes Route Layer This spreadsheet contains information such as the primary direction in which tracks should travel on a given layer horizontal or vertical between pins cost and layer cost Using
10. the design is clean for rerouting Options The Partial option allows tracks to be partially routed during a sweep if the track extends beyond the active routing window The Fast option is recommended for a quick routing or place check it is not recommended for production board routing Via Cost Indicates how conservatively or freely the router will use vias to make connections In other words via cost is calculated as the approximate distance that the router travels in the perpendicular direction the non standard direction horizontal or vertical for the layer before choosing to use a via The default Via Costs are 70 for two and four layer through hole boards and 40 for almost all other multilayer and SMT boards Retry Cost Represents the approximate number of times the router tries to shove tracks aside before it rips up the track or routes through the track Using values of 30 or 60 the router is not likely to rip up the track unless the board cannot be easily routed using shove If the router rips up a track or routes through a track it returns to the track to find a new path for it and completes the connection OrCAD Layout Autorouter User s Guide 29 Chapter 3 Using routing strategy files Route Limit Controls the amount of effort the router will use to route a given track That is the higher the route limit the harder the router will try to make a connection regardless of how long or winding the track becomes A Route Lim
11. tool and route a critical net by following the instructions given in To use shove track mode earlier in this chapter To lock a critical net 1 Choose the spreadsheet toolbar button then choose Nets The Nets spreadsheet displays 2 Select the appropriate row using CTRL and the left mouse button 3 From the pop up menu choose Lock OrCAD Layout Autorouter User s Guide 15 Chapter 2 Using autorouting and interactive routing Autorouting a board Once you ve routed the power and ground nets you should disable them for routing and enable the other nets on the board for routing Disabling power and ground To disable the power and ground nets and enable other nets 1 Choose the spreadsheet toolbar button then choose Nets 2 Click once in the title cell of the Routing Enabled column The entire column is highlighted 3 From the pop up menu choose Enable lt gt Disable The Routing Enabled for the VCC and GND nets changes to No and the Routing Enabled changes to Yes for the rest of the nets Running the autorouter LU LQ The autorouter initiates a series of routing passes that systematically route an entire board Tip Before you begin routing the board save your board file The routing strategy file you loaded determines which passes are performed on your board during autorouting You can see which passes are enabled and alter the number of passes performed using the Route Pass spreadsheet See Each pass i
12. track mode 3 high power 13 low power 3 medium power 13 shoving tracks interactively 13 14 single sided boards 19 SMT boards performing fanout 8 preparing for routing 8 spacing parameters for autorouting 33 spreadsheets Route Layer 24 Route Pass 24 Route Spacing 24 Route Sweep 24 strategy files loading 5 sweep technology defined sweeps autorouting 16 editing 25 Maze Route 25 Next 25 Preliminary Route 25 Special Options 25 Win Comp 25 T U technology templates 79 Test Point Settings command 7 test points generating automatically 17 thermal reliefs 6 through holes connecting nets to plane layers 6 preparing boards for routing 6 V Z Via Cost 29 OrCAD Layout Autorouter User s Guide 37
13. 17 Chapter 2 Using autorouting and interactive routing 15 From the Auto menu choose Create Reports The Generate Reports dialog box displays 16 Select the Test Points option select the Save As File option then choose the OK button The TPOINT TXT file is created 17 From the File menu choose Text Editor A Notepad window displays 18 From the Notepad window s File menu choose Open 19 Locate and select the TROINT TXT file then choose the Open button Test Point Settings dialog box I Generate test points from vias F Allow test points under components F Allow through hole as test points Test Point Pitch fo Help Cancel Generate test points from vias When selected this option creates test points from vias that are defined in the Padstacks spreadsheet Allow test points under components When selected this option allows Layout to position newly created test points under board components If you do not select this option Layout can only place test points outside of component outlines Allow through hole as test points When selected this option allows Layout to use through hole pins as test points Test Point Pitch The value you specify for this option determines the minimum spacing allowed between test points 18 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Routing single sided boards LQ LQ LQ When routing a single sided board start with a ne
14. Choose the spreadsheet toolbar button then choose Padstacks The Padstacks spreadsheet displays Select a cell in the Padstack or Layer Name column that contains the name of a via that shows all layers as Undefined All of the cells pertaining to that particular via are highlighted in black From the pop up menu choose Properties The Edit Padstack dialog box displays Enter values for Pad Width and Pad Height select the Use For Test Point option then choose the OK button Close the Padstacks spreadsheet Choose the spreadsheet toolbar button then choose Nets The Nets spreadsheet displays Using the left mouse button and the CTRL key select nets that need test points From the pop up menu choose Properties The Edit Net dialog box displays Select the Test Point option then choose the OK button Close the Nets spreadsheet Route the board to completion From the Options menu choose Test Point Settings The Test Point Settings dialog box displays Select the options of your choice see the description of the options in this chapter then choose the OK button Layout places test points on each of the nets you specified From the Auto menu choose Design Rule Check The Check Design Rules dialog box displays Choose the Clear All button then select Test Point Violations and choose the OK button Layout notifies you of any errors that were found Correct any test point violations OrCAD Layout Autorouter User s Guide
15. OrCAD Layout Autorouter User s Guide Copyright 1998 OrCAD Inc All rights reserved OrCAD OrCAD Capture OrCAD Layout and OrCAD PSpice are registered trademarks of OrCAD Inc Enterprise CIS Enterprise Component Information System OrCAD Capture CIS OrCAD Express OrCAD Express CIS OrCAD Layout Engineer s Edition OrCAD Optimizer and SmartRoute are trademarks of OrCAD Inc Microsoft Visual Basic Windows Windows NT and other names of Microsoft products referenced herein are trademarks or registered trademarks of Microsoft Corporation All other brand and product names mentioned herein are used for identification purposes only and are trademarks or registered trademarks of their respective holders MN 01 5045 Third Edition 1 July 98 Technical support Corporate offices OrCAD Japan K K OrCAD UK Ltd Fax General email Technical support email Web site OrCAD Design Network ODN 503 671 9400 503 671 9500 81 45 621 1911 44 1256 38 1 400 503 671 9501 info orcad com techsupport orcad com www orcad com www orcad com odn OrCAD 9300 S W Nimbus Avenue Beaverton Oregon 97008 USA Contents About this manual is se ee de RE El Eg GE GEK ks GN dee Ed Ke es GER Re v Before vou e ai a EA E S ventas v Symbols and Eon veEntOnS sers ese e Wiles tear a ede SEERE EE EL ER v Thekeyboard RE EE E EEEE v TER EE RE r O EE NE EE EE E vi Chapter 1 Introduction to autoroutiNg esse see RE EE EE EE
16. at steps 7 through 9 until all power and ground pins are properly fanned out OrCAD Layout Autorouter User s Guide 9 Chapter 2 Using autorouting and interactive routing The Fanout Seitings dialog box Power Ground V Fanout Power Gnd MF Lock after fanout Disable after fanout Share close vias I Use free vias Signals M Fanout Signals Lock after fanout Share close vias I Use free vias IC Fanout Direction V Inside MV Outside Maximum Fanout Distance 300 Help Cancel Fanout Power Gnd Determines whether Layout implements fanout for power and ground SMD pads Power and ground pads are identified by being enabled on an appropriate plane layer as shown in the Nets spreadsheet Lock after fanout Locks the fanout tracks and vias for power and ground nets after fanout is complete This prevents the autorouter from moving the fanout vias away from their respective pads Disable after fanout Prevents power and ground nets from being routed after fanout is complete This is especially advantageous if you plan to perform autorouting immediately after fanout is complete If fanout fails to complete all pads for the power and ground nets that are enabled a message displays to that effect Share close vias Permits tracks belonging to the same power or ground net to share a single via Use discretion before selecting this option via sharing can result in long fanout tracks or large currents
17. d by adding a pin to the signal Keep in mind that this board modification cannot be back annotated to the schematic See For information on adding pins to nets see Adding and deleting pins connected to nets in Chapter 8 Routing the board in the OrCAD Layout User s Guide Layout automatically recognizes nets that have been properly connected to plane layers by making these nets invisible You may also use the Nets spreadsheet to verify connections to plane layers prior to post processing If the board has a split plane you can verify that the power and ground nets are properly connected to the appropriate plane areas by viewing the plane layers If power and ground display as thermal reliefs then they are indeed connected See For information about split planes see Creating split planes in Chapter 8 Routing the board in the OrCAD Layout User s Guide You can also view the thermal connections using the post process preview For information about viewing thermal reliefs see Previewing thermal reliefs in Chapter 9 Using thermal reliefs and copper pour zones in the OrCAD Layout User s Guide 6 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Connections to the planes can be verified prior to post processing by verifying that only nets connected to the planes are enabled then viewing the Statistics spreadsheet to verify that these nets are 100 routed To verify connections to the
18. d to try to rip up unneeded routes OrCAD Layout Autorouter User s Guide 27 Chapter 3 Using routing strategy files Editing route pass parameters You can enable and disable sweeps and sweep passes using the Route Pass spreadsheet You can also access and modify some of the routing parameters set in your strategy file such as via cost retry cost route limit and attempts as Note There is usually no benefit in running multiple passes per sweep The three passes per sweep listed in the Route Pass spreadsheet are there as alternatives and are intended to be run one pass per sweep To edit route pass information 1 Choose the spreadsheet toolbar button choose Strategy then choose Route Pass The Route Pass spreadsheet displays 2 Double click in a cell in the Route Pass spreadsheet The Edit Route Pass dialog box displays 3 Select the Enabled option to enable the pass for autorouting The Edit Route Pass dialog box 21 Passes Enabled T Done Heuristics C Fanout C Maze C Via Reduce C Auto DFM C Auto CDE lk p Options C Partial Via Cost ECLI r Retry Cost GLI r Route Limit GLI r Attempts GLI gt Help Cancel Enabled Select the Enabled option to enable or re enable the pass Done The Done checkbox is selected after the autorouter has completed the pass you re editing 28 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files
19. ds to the thermal relief connection Before you implement power and ground fanout you must assign the power and ground nets to plane layers so that the router will recognize these nets as voltage nets rather than signal nets See For instructions on assigning nets to plane layers see Enabling layers for routing in Chapter 4 Setting up the board in the OrCAD Layout User s Guide To fanout power and ground 1 From the Options menu choose Fanout Settings The Fanout Settings dialog box displays 2 Select the Fanout Power Gnd option and your choice of the options under it See the description of the options in this chapter Deselect the Fanout Signals option 4 Ifyou want fanout to place vias inside or under SMDs select the Inside option 5 If you want fanout to place vias outside SMDs select the Outside option 6 Inthe Maximum Fanout Distance text box specify the maximum distance from the SMD pad to the fanout via then choose the OK button 7 From the Auto menu choose Fanout then choose Board 8 From the Auto menu choose Design Rule Check Select the SMD Fanout Violations option in the Check Design Rules dialog box then choose the OK button 9 If necessary use the interactive routing modes to route all fanout failures such as No Connection to Plane using the error markers as a guide See For instructions on using the interactive routing tools see Using interactive routing tools in this chapter 10 Repe
20. e autorouter ss BEE Es Ese Ee Re RE ri SEE SE Ab ese Ee be ee KERE REKE ge ge ae Ed 16 Generating test points automatically 00 cece see se ee GR Ge Ge Re GR Re Re Ge ee ke ee 17 Routing single sided boards sees see Ge Ge Re Ge Ge Re Gee GR ee Re RA Ge Re Gee ee 19 Creating jumpers for single sided boards sesse se se ee Ge ee Ge Re GR Re Re ee 22 OrCAD Layout Autorouter User s Guide iii Contents Chapter 3 Using routing strategy files sesse ee EER EE RR EER EE RE EG 23 Editing strategy files iese ese ee ee Ge e Re GRA GR Re GR E ae GR ee Ge ee Ge ee ee ee ee ee 24 Editing route sweep parameters ee se se se ee ee Ge GR Ge de ee eed ee ee 25 Editing route pass parameters inmesini a Ge Re GR ee ek ee 28 Editing route layer parameters uses see se se sd se ee Ge ee GR ee ee GR ee RA Ge RA Ge ee 31 Editing route spacing parameters cee sesse ss se ee Ge Ge ek GR ee GR GR ee ke 33 Me EE EA EE 35 iv OrCAD Layout Autorouter User s Guide About this manual The OrCAD Layout Autorouter User s Guide contains information about autorouting in OrCAD Layout and OrCAD Layout Plus Throughout this manual Layout is used to denote both Layout and Layout Plus This manual only includes information that is specific to autorouting Information that is applicable to both manual routing and autorouting is covered in the OrCAD Layout User s Guide Before you begin Before you can use Layout you must install Mic
21. elect the Inside option 5 If you want fanout to place vias outside SMDs select the Outside option 6 Inthe Maximum Fanout Distance text box specify the maximum distance from the SMD pad to the fanout via then choose the OK button 7 From the Auto menu choose Fanout then choose Board 12 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Using interactive routing tools LO Online DRC design rule check is automatically activated whenever you choose either of the interactive routing tools shove track or auto path route In addition you can only use the interactive routing tools on connections within the DRC box See For information on the DRC box see Defining a DRC box in Chapter 8 Routing the board in the OrCAD Layout User s Guide Shove track mode is considered interactive routing because you are interacting with the automatic push and shove routing capabilities of Layout when you are routing a track Auto path route mode not available in Layout Engineer s Edition is considered interactive routing because you are interacting with the autorouter when it suggests tracks and suggests via placement if you select the Suggest Vias option in the Route Settings dialog box Using shove track mode When you use shove track mode Layout shoves other tracks out of the way of the track that you are currently routing With this mode you can pick up individual connections and ro
22. he Load File dialog box displays Select one of the two jumper strategy files JUMPER_H SF for horizontal jumpers or JUMPER_V SF for vertical jumpers You should choose the strategy that corresponds to the longer axis of your board horizontal or vertical Choose the Open button Adjust the DRC box to encompass the entire board If this is not possible make the DRC box as large as possible LL See For information on the DRC box see Defining a DRC box in Chapter 8 Routing the board in the OrCAD Layout User s Guide 16 17 18 19 Route the board From the Options menu choose Jumper Settings The Jumper Lengths dialog box displays Enter the appropriate data then choose the OK button From the Tool menu choose Jumper then choose Convert to Components All of the jumpers created during routing are automatically converted into jumper components and display both in the parts list and on the silkscreen layer 20 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing LU To route a single sided board starting with an existing board file 1 Choose the spreadsheet toolbar button then choose Layers The Layers spreadsheet displays 2 Double click on the row of the layer that you want to designate as a jumper layer The Edit Layer dialog box displays 3 Select the Jumper Layer option then choose the OK button The router automatically creates a jumper on that layer if needed
23. hove technology sweep technology gridless autorouting 2 SmartRoute 2 ground connecting to plane layer 6 fanout 9 verifying connection to plane layer 7 interactive routing 13 interactive routing tools auto path route 2 defined 2 shove track 2 J K Jumper command 20 21 22 jumper layer 19 Jumper Settings command 20 21 jumpers 19 jumpers creating for single sided boards 22 L M Layer Cost 317 layers parameters for autorouting 31 library manager 19 Load command 5 20 loading routing strategy file 5 Lock command 15 21 36 OrCAD Layout Autorouter User s Guide N O nets connecting to plane layers 6 disabling 16 pre routing critical 75 verifying connection to plane layer 7 P Q passes in autorouting 28 plane layers connecting nets 6 verifying connection of nets 7 power connecting to plane layer 6 fanout 9 verifying connection to plane layer 7 pre routing critical nets 75 Primary Direction 32 Properties command 17 19 R resizing DRC Route Box 27 Retry Cost 29 Route Layer spreadsheet 24 Route Limit 30 Route Pass spreadsheet 24 Route Settings command 13 15 Route Spacing spreadsheet 24 Route Sweep spreadsheet 24 routing auto path route 73 interactive 13 shove track 13 shoving tracks interactively 13 14 routing modes auto path route mode 5 interactive 2 shove track mode 3 Index S shove technology defined 7 shove
24. it of 75 or 80 is the recommended value for route limit You should always try to route to 100 or very close of the connections the first time through the window so Route Limit should not be set low unless you purposely do not want to route to 100 of the window for instance if vias are prohibited and you really do not expect the router to route 100 of the window Attempts Specifies the number of tries that the router makes on each connection in the current routing window Attempts should be set within the range of 2 to 25 depending on whether you want the router to route 100 of the connections or not An Attempts setting of 25 routes to 100 or very close A setting of 10 routes 98 of most boards a setting of 5 routes 95 of most boards and a setting of 2 routes 90 of most boards On the other hand a low number of attempts routes the board more quickly 30 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files Editing route layer parameters You set general routing criteria such as layer cost primary direction and between pins cost by editing the data in the Route Layer spreadsheet To edit route layer information 1 Choose the spreadsheet toolbar button choose Strategy then choose Route Layer The Route Layer spreadsheet displays 2 Double click in a cell in the Route Layer spreadsheet The Edit Layer Strategy dialog box displays 3 Set the parameters for Layer Cost Primary Direction
25. le if the manual instructs you to type cd directoryname you type the letters cd followed by a space and the name of a directory For example for a directory named CIRCUITS you would type ed circuits Examples of syntax netlist output and source code are displayed in monospace font For example NOOO1 U1 8 U2 1 Vi OrCAD Layout Autorouter User s Guide Chapter 1 Introduction to autorouting Layout features two autorouting options a gridded autorouter and a gridless shape based autorouter Gridded autorouter Layout s gridded autorouter has two key features sweep technology which allows you to specify the directional emphasis for routing different boards and shove technology which minimizes vias and allows extremely dense autorouting In addition you can use interactive routing tools see Interactive routing tools below with the gridded autorouter to refine the process of autorouting Sweep technology LQ The autorouter routes the board using sweeps which are successive routing passes Beginning at a specified point Layout routes the board continually according to the sweep direction you specify For example if you want the sweeps to progress up first and then to the left the autorouter routes vertically and then horizontally working through the entire board See For information on setting sweep direction see Editing route sweep information in Chapter 3 of this manual Shove technology gt The
26. nd how to optimize autorouting results using interactive routing tools See This chapter describes processes and modes relevant to autorouting and interactive routing tools Layout commands and modes for manual routing are covered in Chapter 8 Routing the board in the OrCAD Layout User s Guide You probably performed the following tasks when you set up the board and placed components If not you need to do so to prepare the board for routing Designate appropriate layers as plane layers or routing layers Define vias Set or verify net properties Run Placement Spacing Violations and correct any spacing violations See For information on designating plane layers defining vias and setting net properties see Chapter 4 Setting up the board in the OrCAD Layout User s Guide For information on running Placement Spacing Violations see Chapter 7 Placing and editing components in the OrCAD Layout User s Guide OrCAD Layout Autorouter User s Guide 3 Chapter 2 Using autorouting and interactive routing After you have completed the above items you are ready to begin the routing process The steps in the autorouting process are Check the board outline via definitions and routing and via grids LU See For information on checking the board outline via definitions and routin 8 8 and via grids see Checking the board outline via definitions and routing and via grids in Chapter 8 Routing the board in the OrCAD Layout Use
27. ng and editing obstacles in the OrCAD Layout User s Guide For information on the library manager see Chapter 14 Creating and editing footprints in the OrCAD Layout User s Guide 4 Select an Obstacle Type from the drop down list then choose the OK button 5 Place the route keepout on the jumper layer 6 When opening a new board select one of the following technology templates in the Load File dialog box JUMP5535 TCH JUMP6035 TCH or JUMP6238 TCH See For instructions on opening a new board see Chapter 2 Getting started in the OrCAD Layout User s Guide See For descriptions of JUMP5535 TCH JUMP6035 TCH and JUMP6238 TCH see Appendix A Understanding the files used with Layout in the OrCAD Layout User s Guide OrCAD Layout Autorouter User s Guide 19 Chapter 2 Using autorouting and interactive routing 7 10 11 12 13 14 15 Create a board outline and set up other desired board criteria using the instructions in Chapter 4 Setting up the board in the OrCAD Layout User s Guide Open the Layers spreadsheet and double click on the jumper layer The Edit Layer dialog box displays Choose the Jumper Attributes button The Jumper Lengths dialog box displays Enter the appropriate values then choose the OK button Select preplaced components by pressing CTRL and clicking the left mouse button Press L to lock the components in position Place the rest of the board From the File menu choose Load T
28. ng the files used with Layout in the OrCAD Layout User s Guide To load a routing strategy file 1 From the File menu choose Load The Load File dialog box displays 2 If necessary change Files of type to Strategy 3 Select a routing strategy file SF then choose the OK button Tip Layout provides two types of strategy files placement strategy files and routing strategy files Although both types of files have a SF extension placement strategy files begin with the letters PL OrCAD Layout Autorouter User s Guide 5 Chapter 2 Using autorouting and interactive routing Routing power and ground on predominantly through hole boards LQ LQ If you are working with a through hole board you must verify that all power and ground nets are connected to the proper plane layers before autorouting If they are not you must complete these connections for example an edge finger needs to be routed to a via for connection to the plane On through hole boards the appropriate nets are automatically attached to the plane layers with thermal reliefs If the power or ground nets did not connect to the plane layers one of three errors may have occurred in the netlist The global power pin is not defined in the part The pin is not connected to the proper signal If the pin is connected it does not have the correct signal name To remedy the problem either modify the schematic and annotate it again or modify the boar
29. oute Settings Layout displays potential via locations as you re routing and removes them if they re not needed in the final version of the track 14 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing To set interactive autorouting options for auto path route mode 1 From the Options menu choose Route Settings The Route Settings dialog box displays 2 Select the Auto Path Route Mode option select one of the following options then choose the OK button Allow Off Grid Routing This option allows auto path route mode to display possible routing paths without regard to the routing grid Selecting this option is the only way to permit auto path route mode to end tracks at an obscure angle of approach Off grid routing is almost always needed for mixed pitch boards Shove Components This option allows auto path route mode to shove components in much the same way as it shoves tracks That is when you place a vertex using the left mouse button or SPACEBAR any imposing components are moved away from the vertex unless those components are locked Maximize 135 Corners This option allows auto path route mode to optimize routing space with vertices of 135 or 90 If deselected the autorouter creates 90 corners only Pre routing critical nets Before autorouting you should route critical nets manually and lock them to the board To route a critical net W Choose an interactive routing
30. pacing Track to track spacing specifies the minimum space required between tracks of different nets and between tracks and obstacles of different nets Note that the generic track to track spacing set here can be overridden on a per net basis using the Net Spacing By Layer dialog box which is accessed from the Edit Net dialog box from within the Nets spreadsheet Track to Via Spacing Track to via and obstacle to via spacing specifies the minimum space required between vias and tracks of different nets Track to Pad Spacing Track to pad and obstacle to pad spacing specifies the minimum space required between pads and tracks of different nets Via to Via Spacing Via to via spacing specifies the minimum space required between vias of different nets OrCAD Layout Autorouter User s Guide 33 Chapter 3 Using routing strategy files Via to Pad Spacing Via to pad spacing can be used to specify the minimum space required between pads and vias of the same net as well as different nets which is the usual case For example if you wish to keep a distance of 25 mils between your SMT pads and the fanout vias that are connected to the pads set Via to Pad Spacing to 25 Pad to Pad Spacing Pad to pad spacing specifies the minimum space required between pads of different nets 34 OrCAD Layout Autorouter User s Guide A Attempts 30 auto path route mode 5 allow off grid routing 15 maximize 135 corners 15 shove components 5
31. planes 1 Choose the spreadsheet toolbar button then choose Statistics The Statistics spreadsheet displays If necessary respond to the message asking if you want to repour copper by choosing the Yes button Scroll until you find the Routed row which is the beginning of the routing data You should see a value of 100 in the Enabled column for Routed which indicates that the appropriate nets are connected to the plane layers If the value is anything less than 100 choose the refresh all toolbar button If the value is still anything less than 100 minimize the Statistics spreadsheet choose a routing tool and route the net to the appropriate plane layer Maximize the Statistics spreadsheet then choose the refresh all toolbar button After you ve verified that the value in the Enable column for Routed is 100 close the Statistics spreadsheet OrCAD Layout Autorouter User s Guide 7 Chapter 2 Using autorouting and interactive routing Fanout on boards with surface mount devices Before routing a board with surface mount devices SMDs you must perform fanout to connect the power and ground nets to the plane then run Design Rule Check DRC to verify that fanout is complete Fanout is a method for facilitating route operations for surface mount pads on a board It is the process of routing an SMD pin to a via so that the connection to the component can be routed on other layers For power and ground pads the ta
32. r s Guide Load a routing strategy file On predominantly through hole boards verify connections to the planes On SMT boards implement fanout for power and ground Pre route critical nets Implement autorouting Optimize routing using the interactive routing tools Check for route spacing violations and check routing statistics LL See For information on checking for route spacing violations and checking routing statistics see Checking routing in Chapter 8 Routing the board in the OrCAD Layout User s Guide Optimize routing using Layout s routing commands LL See For information on optimizing routing with Layout s routing commands see Optimizing routing using Layout s routing commands in Chapter 6 Routing the board in the OrCAD Layout User s Guide 4 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Loading a routing strategy file LQ A routing strategy file determines which default routing layers to use when to use vias which direction the track should travel which colors to use for routes and the size of the active routing window There are many routing strategy files provided with Layout among which are files for two layer four layer six layer and eight layer boards Load the routing strategy file that is most suitable for your board See For a complete list of the routing strategy files provided with Layout see Strategy files in Appendix A Understandi
33. r example if you select the Up Left option the router travels up and down the columns from the defined DRC box working first from the right to the left side of the board That is it finishes routing each column before moving to the next column to the left Each time the router reaches the edge of the board it returns to the defined DRC box before continuing 26 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files LO Route Box You can change the size of the DRC box using this option Changing the size of the DRC box is usually the only adjustment you have to make in the Sweep Edit dialog box The default route box size is 250 x 200 Note The DRC Route Box sizes are in grid units For instance with a 25 mils grid there are 40 grids per inch meaning that a 250 x 200 window would actually be 6 25 x 5 inches The following values are recommendations 20 mils or 25 mils grid 5 mils 81 3 mils or 10 mils grid Default 250 x 200 250 x 200 Maximum 300 x 250 350 x 300 See For information on the DRC box see Defining a DRC box in Chapter 8 Routing the board in the OrCAD Layout User s Guide Overlap X Y The Overlap percent determines the amount of space the router uses to reroute tracks as it moves from window to window It is recommended that you leave these values at the default If the overlap is too small you could end up with many small partial routes If the overlap is too big the router will ten
34. rget via is attached to a power or ground plane using a thermal relief Fanout is especially useful for Multilayer boards that include power and ground planes Densely packed boards that do not permit routing on surface layers Boards that include fine pitch components that impede surface routing Fanout is commonly used to route the power and ground layers of an SMT board However you can also perform full board fanout which is sometimes helpful for routing dense multilayer SMT designs Layout has three fanout commands Board DRC Route Box and Component Board implements fanout for the entire board DRC Route Box implements fanout for all SMD components within the DRC Route Box represented on screen by a rectangle with a dashed border Component implements fanout for a selected SMD component Each command performs fanout on a different scale at the board level a user specified area the DRC Route Box and the component level You can modify options for all three within the Fanout Settings dialog box available by choosing Fanout Settings from the Options menu 8 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Implementing power and ground fanout LQ LQ Power and ground fanout must occur before any signal routing Power and ground fanout connects all surface mount power and ground pins to the appropriate plane layer This is done by means of a via that exten
35. rosoft Windows on your computer then install Layout For information on installing Windows see your Windows documentation To install Layout follow the installation instructions that accompany Layout Symbols and conventions OrCAD printed documentation uses a few special symbols and conventions The keyboard The keys on your keyboard may not be labeled exactly as they are in this manual All key names are shown using small capital letters For example the Control key is shown as CTRL the Escape key is shown as ESC Keys are frequently used in combinations or sequences For example SHIFT F1 means to hold down the SHIFT key while pressing F1 ALT F A means to press and release each of these keys in order first ALT then F then A Arrow keys is the collective name for the UP ARROW DOWN ARROW LEFT ARROW and RIGHT ARROW keys To choose a command from a menu you can use the mouse or press a key combination For example from the File menu choose Open ALT F O OrCAD Layout Autorouter User s Guide V About this manual Text Text you are instructed to type is shown in bold For example if the manual instructs you to type max you type an asterisk a period and the lowercase letters max The text you type is usually shown in lowercase letters unless it must be typed in uppercase letters to work properly Placeholders for information that you supply such as filenames are shown in italic For examp
36. rs are created wherever Layout is unable to find a suitable jumper component for a via pattern that exists on the board or if component to component violations are created in the process of inserting the jumpers Layout replaces the padstacks originally assigned to the jumpers with the padstacks assigned to the vias that were used during routing as long as you use the default jumper padstack name J1 If you do not want the router to route jumpers under components include a keepout area on the jumper layer in the footprints that you create for the single layer boards by duplicating the existing place outline onto the jumper layer and converting the copy into a route keepout 22 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files LU Routing strategy files determine which default routing layers to use when to use vias in which direction the track should travel and the size of the active routing window They also set up the appropriate graphical display for routing This chapter lists and describes the routing strategies included with Layout and explains how to edit routing strategy files The parameters for the strategy files provided with Layout are set according to the type of board component type and number of layers for which the strategy file is intended In most circumstances these parameters do not need to be changed Changing the parameters can negatively affect routing results See For a complete
37. s described and the process for enabling passes is explained in Editing route pass parameters in chapter 3 of this manual The autorouter begins its initial pass inside the DRC box By default the DRC box is located on the densest area of a board You may choose however to customize and specify the size and location of the DRC box See For information on defining and moving a DRC box see Defining a DRC box in Chapter 8 Routing the board in the OrCAD Layout User s Guide To run the autorouter 1 From the Auto menu choose Autoroute then choose Board The autorouter runs the passes specified by the routing strategy file you loaded 2 Either run additional passes on the board or optimize the board using Layout s interactive routing tools 16 OrCAD Layout Autorouter User s Guide Chapter 2 Using autorouting and interactive routing Generating test points automatically Before you can have Layout generate test points automatically you must specify which vias and nets you want to use for this purpose Having done this you can run the test point routine which adds test points to vertices corners on relevant nets After Layout completes this process you can check the board for test point violations and create an index of test points in a test points text file TXT e Caution Do not use Via as a test point It is used as the default by the router To generate test points automatically 1 11 12 13 14
38. s of the router The router finishes each routing window to as close to 100 as possible then moves to the next window Sweeps 3 4 and 5 Next 1 Next 2 and Next 3 The Next sweeps should be used after the autorouter has completed a full sweep through the board preferably when the board has been routed to 93 or better x Tip Another good strategy to use after Maze 1 and Maze 2 is to set a smaller routing grid if legal and run Maze route again Reduce the grid by a factor of one to three For example if your routing grid is set to 25 you could try running Maze route using a grid of 813 The first Next sweep cycles through the remaining connections on the design quickly completing the board if possible but leaving any extremely difficult connections for later sweeps The second and third Next sweeps attempt each remaining connection up to 100 times in order to route the board to completion Unlike a sweep that has a primary and secondary direction a Next sweep uses the Route Next Connection setting as its guide As a result the router does not follow a set pattern through the board but instead searches for unrouted connections centering the routing window on each one in turn If you run the Next sweeps and there are still connections left to route you can run another Next sweep using one of the other two passes Sweep 6 Special Options This sweep has three distinct purposes to run a fast route to determine routing ability
39. ssible make the DRC box as large as possible 12 Route the board 13 From the Options menu choose Jumper Settings The Jumper Lengths dialog box displays 14 Enter the appropriate data then choose the OK button 15 From the Tool menu choose Jumper then choose Convert to Components All of the jumpers created during routing are automatically converted into jumper components and display both in the parts list and on the silkscreen layer OrCAD Layout Autorouter User s Guide 21 Chapter 2 Using autorouting and interactive routing Creating jumpers for single sided boards Using the Convert to Components command you can replace fake jumpers with jumper components selected from the footprint library To create jumpers for single sided boards 1 Choose the spreadsheet toolbar button then choose Layers The Layers spreadsheet displays Double click in the row of the layer that you want to designate as a jumper layer The Edit Layer dialog box displays Select the Jumper Layer option then choose the Jumper Attributes button The Jumper Lengths dialog box displays Set options to specify the jumper lengths footprints direction and designator then choose the OK button twice to close the dialog boxes Close the Layers spreadsheet From the Tool menu choose Jumper then choose Convert to Components This converts the routed via patterns into the actual components you have selected from your library Error marke
40. the Route Layer spreadsheet you can edit the route layer parameters set for the board Route Spacing This spreadsheet shows the amount of space the router allocates among various board elements This data is used to assign a specific value to spacing between tracks vias and pads and any combination thereof These values can also vary by layer 24 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files Editing route sweep parameters A sweep is the automatic movement of an active routing window over the entire board area You set general routing criteria such as the size of the DRC box and the sweep direction by editing the data in the Route Sweep spreadsheet The autorouter uses the criteria from Sweeps through 6 but not from Sweep 0 Sweep 0 influences the behavior of the interactive routing tools shove track and auto path route The differences among the sweeps are explained below Sweep 0 Win Comp This sweep sets the criteria for a single window or a component within a window it affects the behavior of the interactive routing tools shove track and auto path route Sweep 1 Preliminary Route This sweep most effectively routes memory components and tracks that can be routed using simple patterns Sweep 2 Maze Route During maze route the router routes connections by attempting different paths This sweep routes the bulk of the tracks on a typical design using the full shove and retry capabilitie
41. the layer For most boards 80 and 20 for horizontal and vertical layers respectively will suffice For the Next sweep move the values towards 49 vertical and 51 horizontal in order to give the router the maximum amount of freedom while still giving the router guidance as to which layer goes in which direction Between Pins Gives the router the best possible path selection and saves the channels between IC pins for short tracks That is the higher the Between Pins option is set the less likely tracks are to be routed between pins 32 OrCAD Layout Autorouter User s Guide Chapter 3 Using routing strategy files Editing route spacing parameters You set general spacing such as track to track track to via track to pad via to via via to pad and pad to pad by editing the data in the Route Spacing spreadsheet To edit route spacing information 1 Choose the spreadsheet toolbar button choose Strategy then choose Route Spacing The Route Spacing spreadsheet displays 2 Double click in a cell in the Route Spacing spreadsheet The Edit Spacing dialog box displays 3 Set the parameters for Track to Track Track to Via Track to Pad Via to Via Via to Pad and Pad to Pad then choose the OK button The Edit Spacing dialog box 17 Layers Track to Track Spacing Track to Via Spacing Track to Pad Spacing fo Via to Via Spacing i dj Via to Pad Spacing Pad to Pad Spacing Help Cancel Track to Track S
42. the pointer Z Tip When you use shove track mode the router does not automatically show you where vias are needed To change layers while routing a track press the key corresponding to the target layer for example to change to the bottom layer press 2 The router clears away tracks around the via you are inserting when you click the left mouse button to accept the first segment on the new layer x Tip While routing if you press the ALT key and click the left mouse button on a track you can begin a new track on another track of the same net which is known as T routing Using auto path route mode When you use auto path route mode not available in Layout Engineer s Edition Layout suggests a possible track when you select a ratsnest or pin As you move the cursor the suggested track changes position When you click the left mouse button auto path route mode places the suggested track using the push and shove routing capabilities of the autorouter thereby clearing away any imposing tracks Note that the final track may not look like the suggested track You can only use auto path route mode with online DRC enabled Attempting to disable online DRC takes you out of auto path route mode x Tip If you double click on a connection auto path route mode routes the track for you automatically When you use auto path route mode with the Suggest Vias option selected in the Route Settings dialog box from the Options menu choose R
43. tlist and a technology template optimized for single sided boards Layout provides three such technology templates JUMP5535 TCH JUMP6035 TCH and JUMP6238 TCH After you create a new board you must create a board outline technology templates do not contain board outlines place the board and load a strategy file that allows for jumper wires Two strategy files for jumper wires are provided with Layout They are JUMPER_H SF for horizontal jumpers and JUMPER_V SF for vertical jumpers You can also create a single sided board using an existing board file This section describes both processes To route a single sided board starting from a netlist 1 Choose the library manager toolbar button The library manager displays Caution Do not permanently alter or modify any standard footprints Use the Save As command in the library manager to create new footprints 2 Create route keepouts for all of the footprints that will be placed on the jumper layer this keeps the jumper vias outside of the components by selecting a library and a part in the library manager The relevant footprint displays in the footprint editor 3 Select the place outline of the footprint by clicking on it with the left mouse button Choose Copy from the pop up menu then choose Properties from the pop up menu The Edit Obstacle dialog box displays See For information on editing and copying obstacles see Editing obstacles and Copying obstacles in Chapter 5 Creati
44. to reduce the number of vias on a board and to smooth and straighten corners OrCAD Layout Autorouter User s Guide 25 Chapter 3 Using routing strategy files To edit route sweep information 1 Choose the spreadsheet toolbar button choose Strategy then choose Route Sweep The Route Sweep spreadsheet displays 2 Double click in a cell in the Route Sweep spreadsheet The Sweep Edit dialog box displays 3 Edit the options as desired then choose the OK button The Sweep Edit dialog box 7 Sweeps Diagonal Routing ae z E Off C On C Maximize r Sweep Direction Route Box C Up Left C Up Right es C Down Left C Down Right C Right Up C Right Down N C Left Up C Left Down C Route Next Connection Oe ee mm mm Y Help Cancel Diagonal Routing Enable or disable diagonal routing If you select the Maximize option Layout uses a 45 angle to route a connection whenever possible except if a 90 angle is necessary to clear pads and obstacles during routing Maximize is the default because routing at 45 angles is recommended to minimize the number of segments on the board Sweep Direction When performing sweeps the router divides the board into equally sized rows and columns The number of rows and columns depends on the size of the route box DRC box During routing the router travels up and down and across the board using these columns in the direction you specify Fo
45. ute them aided by the shove capability manually route critical tracks and edit tracks and vertices To set routing parameters for shove track mode 1 From the Options menu choose Route Settings The Route Settings dialog box displays 2 Select the Shove Track Mode option select one of the following options then choose the OK button Low Power The router moves tracks only slightly or conservatively in an attempt to move them out of the way as you add new tracks Medium Power The router shoves tracks and may even push routes over other items such as pads and around other tracks in an attempt to move them out of the way as you add new tracks High Power The router rips up shoves and reroutes existing tracks as you add new tracks OrCAD Layout Autorouter User s Guide 13 Chapter 2 Using autorouting and interactive routing To use shove track mode 1 Choose the shove track toolbar button 2 Define the DRC box size to encompass your area of interest 3 Select a connection with the left mouse button The connection attaches to the pointer 4 Drag the pointer to draw a track on the board Click the left mouse button or press the SPACEBAR to create vertices corners in the track 6 When drawing the last segment for the connection choose Finish from the pop up menu The track automatically connects to the center of the pad A complete connection is indicated by the cursor changing size and the ratsnest disappearing from

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