Exercise 1. Section 2. Working in Capture

Transcription

1 Exercise 1 Section 1. Introduction In this exercise, a simple circuit will be drawn in OrCAD Capture and a netlist file will be generated. Then the netlist file will be read into OrCAD Layout. In Layout, you may create the PCB board outline, assign footprint to every component (or create new footprints if there is no desired footprint available in the footprint library), and define the layer stack and grids. After that, you will be able to place components onto the PCB board. Routing connections between components will be the next step. After a few checking and cleaning steps, the design of a PCB board will be finished. In the DIAGRAM.PDF file, there are the materials you may need to design the PCB board using OrCAD, including the schematic diagram of the circuit and the physical dimensions, as well as the pad layouts, of the components. Section 2. Working in Capture Fig.1. PCB design flow To create a new project, a new design, and a new schematic page: 1. Open Capture. 2. From the File menu, choose New, and then choose Project. The New Project dialog box appears. 3. Type a name for your new project in the Name text box. 4. Use the Browse button to select a new directory. 5. Select a project type in the Create a New Project Using group box, and click OK. A new project is then created. 6. From the File menu, choose New, then choose Design. 7. The design opens in a new PCB project manager and a new schematic page displays. A new design is then created. 8. On the File tab of the project manager, select the schematic folder that requires a new schematic page.

2 9. Click the right mouse button and choose New Page from the pop-up menu. A new schematic page appears within the schematic folder you selected in the previous step. Capture includes libraries with a total of over 30,000 parts that you can use on your schematic pages. You can also create your own parts. To create new parts or to edit existing parts using parts editor: 1. In the project manager, open a new library or select an existing library. From the right mouse button s pop-up menu, choose New Part. The New Part Properties dialog box appears. 2. In the Name text box, type a name for the part you are creating. You can use the default settings for the other options on this dialog box, or you can change them to fit your requirements. Then click OK. 3. The part editor window appears, showing a dashed outline, which is the part body border. Pins will be placed on the part outside of this region, touching the part body border. You may drag the part body border to change the size and shape of it. 4. Once you have established the part s border, you can use the drawing tools on the part editor s tool palette to draw the part and place text on the part. You can add pins to the part using the pin tool or the pin array tool. 5. When you are done creating the part, from the File menu, choose Save to save the part in the library you selected before. 6. To edit an existing part, open a library in the project manager, then double-click on the part. To edit a part instance on a schematic page, select it. From the Edit menu, choose Part. To place parts, symbols, and wires: 1. Choose the part tool on the schematic page editor s tool palette. The Place Part dialog box appears. Select a part from the list that appears. 2. Or in the Part text box, type the name of the part. If you aren t sure of the name of the part, enter wildcard characters to constrain the list of parts, then click OK. Valid wildcard characters are an asterisk (*) to match multiple characters and a question mark (?) to match a single character. When you have located the part you want to place, click OK. 3. An image of the selected part is attached to your pointer. You can click the right mouse button to display a pop-up menu with commands that you can use to change the properties of the part before you place it. 4. Move the pointer to the location on your schematic page where you want to place the part, then click the left mouse button. 5. When you are done placing instances of the selected part, choose End Mode from the right mouse button pop-up menu, or press ESC. 6. To place a power or ground symbol, choose the power tool on the schematic page editor s tool palette. The Place Power dialog box appears. Select the power or ground symbol you want and place it onto the schematic page using the same way as placing a part.

3 7. To place a no-connect symbol, choose the no-connect tool on the schematic page editor s tool palette. Position the mouse over the pin end and click the left mouse button. The end of the pin changes from a square (unconnected) to an X (not connected). 8. To place a wire, choose the wire tool on the schematic page editor s tool palette. Click the left mouse button to start the wire. Move the mouse to draw the wire. Click the left mouse button if you want to place a vertex and change directions. Clicking on another wire connects the two wires. Double-click to end the wire. When you are done placing wires, choose End Mode from the right mouse button pop-up menu, or press ESC. To find a part in Capture s library: 1. In the schematic page editor, choose Part from the Place menu. 2. Click the Part Search button. The Part Search dialog box appears. 3. Enter the part name you want to locate. 4. Click Browse to locate the directory where your libraries are located. 5. Click Begin Search. Capture returns the names of all the libraries, which contain your part, in the specified directory. To annotate after finishing the schematic drawing: 1. In the project manager, select the schematic pages on which to annotate. 2. From the project manager s Tools menu, choose Annotate. The Annotate dialog box displays. 3. Set the options in this dialog box as necessary. Click OK to begin the update. To check for design rules violations: 1. In the project manager, select the schematic pages that you want to check for design rules violations. 2. From the project manager s Tools menu, choose Design Rules Check. The Design Rules Check dialog box appears. 3. Select the settings you want in the Design Rules Check tab and in the ERC Matrix tab, then click OK. 4. Once the design rules check is complete, you can view the result report file by double-clicking on the file in the project manager to bring it up in the text editor. To create a netlist file for Layout: 1. In the project manager, select your design. 2. From the Tools menu, choose Create Netlist. The Create Netlist dialog box displays. 3. Choose the netlist format tab to be Layout. 4. In the Netlist File text box, either use the default name or enter a name for the output file. 5. Click OK to create the netlist. To create a bill of materials report file:

4 1. From the project manager s Tools menu, choose Bill of Materials. The Bill of Materials dialog box displays. 2. Fill in this dialog box as desired. Click OK when you are ready to create the report. 3. After the bill of materials is generated, you can double-click on its name in the Output folder in the project manager to view it in the text editor. The best way to view a bill of materials is to open it in a spreadsheet program such as Microsoft Excel. Section 3. Working in Layout To start a new design: 1. From the File menu, choose New. The Load Template File dialog box appears. 2. Select default board template DEFAULT.TCH, then choose the Open button. The Load Netlist Source dialog box appears. 3. Select the netlist file (.MNL), which has been created in Capture, then choose the Open button. The Save File As dialog box appears. 4. Supply a name for the new board file (.MAX), then choose the Save button. AutoECO runs automatically, and displays its progress in an ASCII report file (.LIS). If there are no AutoECO errors, the new board opens in Layout s design window. 5. If there is missing footprint during the processing of AutoECO, you may choose the Create or Modify Footprint Library button to generate new footprints for your parts, or choose the Defer Remaining Edits Until Completion button to continue running AutoECO and generate new footprint later. To create a board outline: 1. From the Tool menu, choose Dimension, then choose Datum. Click on the lower left corner of the board outline to place the datum (to provide a starting grid for component placement). Press Home to redraw the screen. 2. Choose the obstacle toolbar button. 3. From the pop-up menu, choose New, then from the pop-up menu, choose Properties. The Edit Obstacle dialog box appears. 4. From the Obstacle Type drop-down list, select Board outline. In the Width text box, enter 50 (mil) for the outline s width. From the Obstacle Layer drop-down list, select Global Layer, then choose the OK button. The Edit Obstacle dialog box closes. 5. Move to the point on the board at which you want to start drawing the outline, then click the left mouse button to insert the first corner. Continue clicking the left mouse button to insert corners. After you click to insert the last corner, choose Finish from the pop-up menu. Layout automatically completes the board outline. To define layer stack for routing: 1. Choose the spreadsheet toolbar button, then choose Layers. The Layers spreadsheet appears.

5 2. Choose the TOP and BOTTOM layers as routing layers. To disable a layer, double-click on it, then specify it as Unused Routing in the Edit Layer dialog box. 3. Choose the OK button. The layout has a group of pads defined as below. T1: Round IC pads T2: Square IC pads T3: Round discrete pads T4: Square discrete pads T5: Round connector pads T6: Square connector pads T7: Via SMT stringer pads When you are going to define a customer pad, don not use names T1 through T7. To create a new padstack: 1. Choose the spreadsheet toolbar button, then choose Padstacks. The Padstacks spreadsheet appears. 2. Select a padstack that is similar to the one you want to create, then choose New from the pop-up menu. A new padstack is added at the bottom of the spreadsheet. 3. Select the new padstack and choose Properties from the pop-up menu. Type a new name for the padstack in the Padstack text box, edit the other options to change the size or shape as desired, then choose the OK button. To create a new footprint for your component: 1. From the File menu, choose Library Manager. 2. In the library manager, choose the Create New Footprint button. The Create New Footprint dialog box appears. 3. Enter a name for the new footprint. If the footprint is to be a metric footprint, select the Metric option. Choose the OK button. The footprint origin, one pin, and default text objects display in the footprint editor. 4. You can add pins by pressing the pin toolbar button. From the pop-up menu, choose New. A new pin attaches to the cursor. Position the pin in the desired location and click the left mouse button to place the pin. 5. The footprint outline is used to maintain a specified distance between parts. For surface mount parts, this outline should be large enough to provide sufficient space between parts, thereby eliminating solder shadowing and facilitating the post-assembly inspection process. Drawing an outline for a footprint is similar to drawing an outline for a board. 6. If you want to edit the footprint s pads, double-click on the pad. The Edit Pads dialog box shows up. You can change the settings of the pad, then choose OK button. 7. When you have finished drawing the footprint, choose Save button. Specify the destination library, and then click the OK button. To load a placement strategy file: 1. From the File menu, choose Load. The Load File dialog box appears.

6 2. If necessary, change Files of type to Strategy. 3. Select PLSTD.SF from the list and choose the Open button. After setting up the board, you can place the components onto the board. To place components individually: 1. Choose the component toolbar button. 2. From the pop-up menu, choose Queue For Placement. The Component Selection Criteria dialog box appears. 3. Enter the reference designator (or other criteria) of the component that you want to place in the appropriate text box, then choose the OK button. 4. From the Edit menu, choose Select Next. The component snaps to the cursor. Drag the component to the desired location and click the left mouse button to place it. 5. To place the second component, choose the component toolbar button. From the pop-up menu, choose Place. The Select Next dialog box appears. Select a component for placement, then choose the OK button. To lock the components to the board so that they won t get moved when you are placing other components: 1. choose the Component Tool Bar button. 2. Select the component you want to lock on the board. Then from the pop-up menu, choose Lock. To place components automatically: 1. From Auto menu, choose Place, then Board. To use the Minimize Connections command: 1. Choose the component toolbar button. 2. If desired, select the appropriate component(s) or net(s). 3. From the pop-up menu, choose Minimize Connections. To move a component: 1. Choose the component toolbar button. 2. From the pop-up menu, choose Move On/Off. The component is highlighted, but remains in place. 3. Press the Ctrl key and click the left mouse button to move the component. To delete a component: 1. Choose the component toolbar button. 2. From the pop-up menu, choose Delete. 3. Confirm your decision to delete, and choose the OK button. The component is deleted. To rotate components: 1. Select one or more components.

7 2. From the pop-up menu, choose Rotate. (The default rotation increment is 90.You can change it by choosing System Settings from the Options menu, then enter the number of degrees you want the components to rotate in the Increment text box in the System Settings dialog box. ) To edit components: 1. Select one or more components. From the pop-up menu, choose Properties. The Edit Component dialog box appears. 2. You can edit the component name, the footprint name, create mirrored components, lock or fix components, and enable or disable components for placement using the Edit Component dialog box. To check placing errors: 1. From the Auto menu, choose Design Rule Check. The Check Design Rules dialog box appears. 2. Choose the Clear All button. 3. Select the Placement Spacing Violations option, then choose the OK button. Layout checks the board for component placement violations and marks any errors with circles. After you have completed the above items, you are ready to begin the routing process. To load a routing strategy file: 1. From the File menu, choose Load. The Load File dialog box appears. 2. If necessary, change Files of type to Strategy. 3. Select a routing strategy file (.SF) for two-layer boards, then choose the OK button. To route the board using Autoroute function: 1. If necessary, before autoroute the board, you should route the critical nets manually and lock them onto the board. Refer to the online help for Manual Routing steps. 2. From the Auto menu, choose Autoroute, then Board. To check design rules: 1. From Auto menu, choose Design Rule Check. The check Design Rules dialog box appears. 2. Select from the following options, then choose the OK button. a. Placement Spacing Violations b. Route Spacing Violations c. Net Rule Violations d. Other options 3. When you run Design Rule Check, the errors are marked on the board with circles. To clean up your design:

8 1. From the Auto menu, choose Cleanup Design. To create reports: 1. From the Auto menu, choose Create Reports. The Generate Reports dialog box appears. 2. Select the reports you want generated then choose the OK button.