Interfacing to other design tools

This section outlines how to transfer a schematic design to the PCB Editor using the Synchronizer and netlists.

9.1

Setting the relevant project options

There are a number of settings that control what data is transferred between the schematic design and PCB layout. Select Project » Project Options to display the Options for Project dialog and click on the Comparator tab.

Figure 36. The Comparator options define what information is transferred to PCB.

By default, all options are on. For a simple design such as the training design, you might not want Placement Rooms to be created for each schematic sheet.

9.2

Transferring a design to the PCB Editor

• If you are using Altium Designer's PCB Editor to do the board layout, the best method of transferring design information between the schematic and the PCB (and from the PCB back to the schematic) is the Design Synchronizer. Using the Synchronizer, there is no need to create a netlist in the schematic and load that netlist into the PCB. Selecting Design » Update PCB will start the synchronization process.

• When you have a PCB and select this command, the Engineering Change Order dialog will be displayed. This lists all the changes that must be made to the PCB to get it to match the schematic. This process will be covered in detail during the PCB training module.

• You can also transfer the design using the Project » Show Differences command. This uses the design synchronizer, but gives more comprehensive control of the transfer process.

9.3 Netlist formats

A netlist is an ASCII file that contains the component and connectivity information defined in the schematic. The netlist can be used to transfer component and connectivity information to other design tools, including PCB Design packages from other vendors. Note that you can still use it to transfer to Altium Designer’s PCB editor, but since it does not include unique component ID information it is an inferior method of design transfer.

Netlists are generated by using the Design » Netlist for Project menu. By default, there are seven netlist formats in the menu, including EDIF, Xspice and Multiwire. Other netlist formats are also supported. Download the required netlist generator from the Downloads page of the Altium website (www.altium.com).

9.4

Exercise – setting project options for design transfer

Open the Options for Project dialog, and display the Comparator tab. 1. Set the Extra Room Definitions option to Ignore Differences. 2. Close the dialog and save the project.

10.

Parameters

• Parameters are used to add extra information to sheets, sheet symbols, components, pins and ports. Objects that do not handle parameters through their Properties dialog, such as wires and buses, can have parameters attached to them by using Parameter Sets. • Components will typically have many user-defined parameters, such as electrical design

parameters like voltage or tolerance values, or purchasing and assembly information. This information is included by adding parameters to the schematic components via the

Components Properties dialog, either in the schematic library or on the schematic sheet.

• Parameters can also be used to link the schematic components with a company database, refer to the documents Linking Existing Components to Your Company Database and Using

Components Directly from Your Company Database for more information.

Figure 37. Parameters can are added to schematic components via their Properties dialogs in the Schematic Editor or the Schematic Library Editor.

• System-level parameters are special strings which have the suffix = before the parameter name, such as =CurrentDate or =Revision. These can be added to your sheet’s title block and are updated through the Parameters tab of the

Document Options dialog (Design »

Document Options). See 2.1.2 Parameters

tab for more information. You can update

system-level parameters in multiple documents by using the Parameter Manager.

• Parameters are used to define PCB rules on the schematic. Where you add the parameter dictates the scope of the PCB rule that is created – for example a Parameter attached to a wire will create PCB rule that applies to that net (). Whereas attaching the parameter to a bus would result in a PCB design rule that targets a NetClass.

• To define a rule targeting a net, select Place »

Directives » PCB Layout from the menus. _{Figure 38. Define PCB rules on the schematic}

• Project and document parameters can be extracted from the project and included in the Bill of Materials. Document parameters are included with each component that comes from that document. Project parameters can be mapped to pre-defined Fields in your Excel template, as shown below.

Figure 39. Include project parameters in your BOM by defining Fields in the Excel template.

10.1 The Parameter Manager

• The Parameter Manager allows you to control all your parameters in one single editor. Open the Parameter Manager by selecting Tools » Parameter Manager from the menus. User- defined parameters can be added, removed or renamed in the Parameter Manager. You can modify the values of system-level parameters but these cannot be added, removed or renamed. • You can select which parameters will be included

in the Parameter Table Editor by limiting the types of parameters you wish to use in the

Parameter Editor Options dialog. For example,

you can exclude all system parameters, or only use document-level or part parameters.

• Changes to the values or names of parameters are made in the Parameter Table Editor and then an ECO is generated to execute the changes in the design or schematic library.

Figure 40. Parameters can be modified using the Parameter Table Editor.

Tips for using the Parameter Manager

• Editing in the Parameter Table Editor is similar to editing in an Excel spreadsheet. For example, press F2 or SPACEBAR to edit, type in the value or select it from a drop-down list, if available, and then press Enter. Use the arrow keys to move through the spreadsheet. • You can edit multiple instances of the same parameter value by selecting the cells, right-

clicking and selecting Edit for the drop-down menu. Type in the new value and press Enter. Right-click and choose Revert to undo changes to selected cells.

• Cells are highlighted in the Parameter Table Editor according to whether the parameter exists or has current values.

the object possesses the parameter and the string entry in the field is its value.

the object possesses the parameter, but it currently has no value the object does not possess the parameter.

• When you modify a parameter, markers in the right-hand top corner of the cell indicates what changes will be made.

the value assigned to the parameter will be changed.

the parameter will be added to the object but, in this case, no value will be assigned.

the parameter will be removed from the object.

• Note that any changes made within the table are virtual changes that will not be implemented until the execution of an Engineering Change Order.

10.2 Exercises – Using the Parameter Manager

10.2.1 Adding values to parameters using the Parameter Manager

1. The first exercise will add sheet numbers and the number of sheets using the Parameter Manager.