FlowCAD. FlowCAD Webinar. Constraint Manager Tips and Tricks.

Transcription

1 FlowCAD Webinar Constraint Manager Tips and Tricks

2 FlowCAD Overview Constraint Manager Basic Physical Constraints Spacing Constraints Analysis Mode Differential Pair Total Etch length Constraint Regions This & That

3 FlowCAD Constraint Manager Clearly arranged in different categories All the constraints are defined in one place Constraints can be reused Online Design Rule Check (DRC) Scalable for all future needs The defined constraints are used by the auto router

4 Constraint Manager Because the Constraint Manager is scalable within the different tiers, you may have more rules which can be set. Don t worry, the process is always the same. This presentation is based on a OrCAD PCB Professional 16.5 license

5 FlowCAD Constraint Manager Basic The constraints are separated in different categories: - Electrical - Physical - Spacing - Same Net Spacing - Properties - DRC (Design Rule Check)

6 FlowCAD Constraint Manager Basic Each category contains two main folders: - A Constraint set with the different parameters which can be set - A list of all nets in the design Some categories contains as well: - Regions, for region rules - Net Class, for Net class to net class rules

7 FlowCAD Constraint Manager Basic Function of the Constraint Manager: - Define a constraint - Associate the constraint to a net - Route the design - When a rule is not maintained, an Error will be displayed a DRC Marker appear

8 FlowCAD Constraint Manager Example Each net has the DEFAULT constraint set associated How to define a user defined line width on a specific net: - The Sense net needs a minimum line width of 0.2mm

9 FlowCAD Constraint Manager Example There are two ways to define constraints. First we show how to define constraints for one single net by the override method. For the sense net, the line width is changed to mm. Each value which was changed manually, change the font color to blue and get s bold:

10 Constraint Manager Example The second method is to create a constraint set. This rule set can be associated to a net or to a class of nets. To create a constraint set, select in the left panel the Physcial Constraint Set Folder

11 Constraint Manager Example Define a name for the Physical Constraint Set, example Power: Change the value in the constraint set:

12 Constraint Manager Example Reference the POWER Constraint set to the SENSE Net:

13 Constraint Manager Example When starting to route the sense line, the line width which is defined in the constraint manager, is chosen:

14 Constraint Manager Example When for some reason the line width is smaller than the 0.2mm, a DRC marker appears:

15 Constraint Manager net class Constraint set s can also be referenced to a net class (group of nets):

16 FlowCAD Constraint Manager net class You can define a netclass as described below: - Select the desired nets - Click right mouse button -> create -> class - Define a net class name

17 FlowCAD Constraint Manager net class Another way to create a netclass is: - Select Objects in the Constraint manager - Select create-> Class On an existing netclass, a net can be added or removed as described below:

18 FlowCAD Physical Constraints Line Width Min: Minimum line width Line Width Max: Max. line width, when value= 0, the field is ignored Differential Pair: separate chapter

19 FlowCAD Physical Constraints Neck min Width: Neck Max Length: Neck min width Min line width Neck max length Vias: define the default via

20 FlowCAD Physical Constraints BB Via Stagger: Staggered vias are two pins or vias on the same net with a single connect line connecting them on a particular layer. The stagger distance is the distance from the connect point of one pin or via (x,y location) to the connect point of another. Allow - Etch: defines if a connect line is allowed on a specific layer or not. Allow T s: Specifies whether T-junctions of cline segments are allowed and where they may form (pin, via, cline). Allow - Pad-Pad Connect: Specifies whether a pin/via whose connect point lies within the extents of another pin/via forms a direct connection without the presence of an intermediate cline.

21 Spacing Constraints Define the distance between all the different elements. When selecting the line under the spacing category, you see on the right side the table with all the spacing between line and the other objects.

22 Net class to Net class spacing It is possible to define different spacing for nets in net classes. For such cases the Net Class to Net class spacing can be defined:

23 Net class to Net class spacing

24 Same Net Spacing Constraints Define the distance between all the different elements of the same net. The behavior is similar as in the spacing constraints.!! Don t forget to enable the Same net Spacing under Options!!

25 FlowCAD Analysis Mode!! Each constraint can be enabled/disabled in the analysis mode!! Useful: - For performance reason, constraints can be disabled - constraints can be turned off temporarily

26 Analysis Mode

27 Analysis Mode

28 Analysis Mode Set Design Options constraints enable/disable Design Constraints

29 FlowCAD Differential Pair Process how to set up differential pairs: - Define Differential pairs in the Constraint Manager - Define Constraint Set for Differential pairs in the Constraint Manager - Reference the constraint set to the desired differential pairs

30 Differential Pair Creating Differential Pairs in Constraint Manager

31 FlowCAD Differential Pair Auto Creation of Differential Pairs: 1. In the Net > Routing > Differential Pair of Constraint Manager, select Objects > Create > Differential Pair. 2. In the Create Differential pair dialog, click Auto Setup. 3. Enter Prefix and +/-Filter as desired 4. Select Create to create the differential pairs automatically.

32 Differential Pair Line Spacing Minimum Line Spacing Coupled Tolerance (-) Primary Gap Coupled Tolerance (+)

33 Differential Pair - Differential Pairs can be defined in the Physical worksheet

34 FlowCAD Differential Pair If you need to control the length of Differential Pairs, several options are available: - Total Etch length (Next chapter) - Static phase tolerance (Allegro PCB Designer License) The phase is checked over the entire net from Driver to Receiver. - Dynamic phase tolerance (Allegro PCB Designer + High Speed Option) This rule checks, that even in the entire line section the two nets are always in phase!

35 Differential Pair Uncoupled length The maximum length of the two nets of a differential pair, where they can run uncoupled can be defined with the max uncoupled length constraint.

36 Differential Pair Differential Pairs constraints can be defined in the Electrical or in the physical category. Which should I use?

37 FlowCAD Differential Pair Use Electrical Category: When you need to use phase control (static/dynamic) (Allegro PCB Designer/+High Speed Option) When you need to control the uncoupled length Use Physical Category: When different line width for each layer are required Advise: - Define the Differential pairs constraint only in one of the two categories to prevent confusing.

38 FlowCAD Electrical Constraints: Total Etch length The Total Etch constraint is used to specify the minimum and maximum etch requirements for Xnet or Net. Following DRC appears when Constraint doesn t match:

39 FlowCAD Electrical Constraints: Total Etch length Constraints can be entered in the CMGR -> Electrical Etch Length The Units are the same as in the board layout Don t forget to enable the Rule in the analysis Mode!!

40 FlowCAD Electrical Constraints: Total Etch length During routing you get graphical feedback if the constraint is maintained. A dashed line in the trace means, the min/max rule isn t obtained:

41 FlowCAD Electrical Constraints: Total Etch length If the connect line is to short, the line has to be extended To extend the line length, you can use the Route-> Delay Tune command Define the style in the options window

42 Electrical Constraints: Total Etch length Just add the extension until the dashed line disappears. Cline length is smaller then min. Etch length Cline matches the constraint Cline is longer then max. etch length

43 Electrical Constraints: Total Etch length With Allegro PCB Designer license, you get a graphical feedback within an extra window

44 FlowCAD Constraint Regions Constraint regions can be used to define areas on your pcb where other constraints are valid then otherwise defined. For example on a placed BGA component, you may have to allow smaller connect lines that they can pass the pins. On a constraint region different spacing rules, physical rules or both can be defined. A constraint region can be defined on a single layer or through the entire stack-up.

45 Constraint Regions Constraint Region

46 FlowCAD Constraint Regions Use the add shape command to design a new constraint region Define Constraint region as class Chose the desired subclass to define on which layer the region should be placed. Define a name for the region Draw the region on your PCB

47 Constraint Regions Create a physical constraint set

48 Constraint Regions Define the physical constraints in the BGA_DEMO constraint set as desired: Assign constraint set to the region

49 FlowCAD Properties Worksheet For each net different properties can be set Example: When the No Rat property is set to on, no ratnet is displayed for this specific net

50 FlowCAD Properties Worksheet A lot of Component and Pin properties can be set in this Worksheet. Example: For each pin, the thermal connection within a shape can be defined manually

51 FlowCAD DRC Worksheet Each DRC is listed separately Each DRC can be waived, selected in this table in the right mouse button menu

52 Filter Options When you re searching a special net or pin just enter the name in the field marked with an * in the top row

53 Colouring nets are marked in CMGR Colouring nets in the color dialog: Net is marked in the Constraint Manager:

54 Searching a net on the board When selecting a net chose the Select and Show Element command in the right mouse button. The net will be highlighted.

55 Searching a net in the CMGR When selecting a net in the layout and the constraint manager is open, the net is automatically selected.

56 How to change the value in an entire row? When selecting a net in the layout and the constraint manager is open, the net is automatically selected. 1.Select one entire row: 2.Change one value and all the selected field gets the same value 3.All the value are changed

57 Constraint Reuse Constraints can be exportet/imported in the Constraint Manager: Define a board template with your desired colors, layers and basic constraints.

58 FlowCAD Outlook The constraint Manager is really powerful. You can use it to define relative propagation delay, control wires topology ( ex. Daisy chain), and much more. Requires Allegro PCB Designer License! You can even define your own formulas in the constraint manager! Requires Allegro PCB Designer License! For more detailed information, please look at the Allegro Constraint Manager User Guide or contact FlowCAD.

59 Ende Besten Dank für Ihre Teilnahme und für Ihr Interesse! Für Fragen, Anregungen oder Bemerkungen erreichen Sie mich unter: Tel.: + 41 (0) support@flowcad.ch

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