Placement & Routing. Lab 8. Placing Parts

Transcription

1 Placement & Routing Lab 8 Placing Parts 121

2 Placement and Routing Lab 8: Placing Parts This lesson will show you how to place parts in PADS Layout. Placement can be driven from the schematic or directly within PADS Layout. Schematic-driven placement uses cross-probing from the schematic to quickly and easily target specific parts for placement. When you select the part in the schematic it will automatically snap to the cursor in PADS Layout allowing you to quickly place parts based on the their locations defined in the schematic. This is available from either PADS Logic or PADS Schematic Design environment. Layout-based placement offers a standard select-and-drag method or you may use the Verb mode. The select-and-drag Placing Parts in an Empty PCB Design Propagate Data to Layout with Forward Annotation method allows you to select the desired part and use the cursor to drag it to a new location. If using the Verb mode you can select the part and it will automatically snap to the cursor for placement. Modeless commands are also available to drive placement in conjunction with Verb mode. If you enter the Verb mode and then initiate the modeless command, the specified part will snap to the cursor ready for placement. Parts can be rotated, spun, flipped and glued on an individual basis or as a group. Parts can also be placed at specific coordinates using either a Properties dialog box or via a modeless command (S x y). Project synchronization within PADS allows you to use Forward Annotation to PADS Layout to quickly identify parts for placement. The Project Integration dialog is used to help you know when changes have been made on the schematic that could affect the layout ❶ Double-click the PADS Layout icon on your desktop. ❷ Select File > Open. Browse to E:\PADS_ES_Evaluation\Lesson16\Lesson16.pcb. NOTE: Upon opening click the maximize button in the upper right corner of the interface to best observe and use the status bar. PADS Layout detects that new changes are ready for Forward Annotation using the traffic signal lights in the lower right corner status bar. ❸ Select Setup > Project Integration from the main menu. ❹ The Project Integration dialog displays with information. In the Back Annotation options area, ensure that the Preserve PCB design rules on first Forward Annotation option is not selected. ❷ ❹ Placing Parts L8-1

3 Placement & Routing Lab 9 Interactive Routing 121

4 Lab 9: Interactive Routing PADS offers a number of options for adding trace data to a PCB. There are manual modes that do not error check during the routing process, there are manual modes that will error check and prevent DRC (Design Rule Check) errors, there are interactive auto modes without DRC and there are fully interactive auto modes that will not allow errors. You can add traces using an automated method as well as by copying and pasting. Open Placed Board in PADS Layout Adding traces to a design is one of the most time consuming elements in printed circuit board layout. Being able to route efficiently can make-or-break meeting your project deadline. This exercise will take you through the routing options available in the PADS Layout and Routing environment. ❶ If it is not already running, start PADS Layout and select File > Open. Browse to and open E:\PADS_ES_Evaluation\Lesson18\Lesson18.pcb. NOTE: Use Start > All Programs > Mentor Graphics PCB > PADS VX (32bit) > Layout and Routing > PADS Layout to launch PADS Layout from the Start menu. Manually Routing Traces (DRC OFF) You can manually route using the Add Route button on the Design toolbar. Click to indicate each corner in the trace. This type of routing works in any Design Rule Check (DRC) mode. ❶ Click the second icon in the upper right corner of the PADS Layout window to change to full screen mode for this exercise. Next, (with no object selected) right-click inside the workspace area and click Select Anything from the menu that appears. Using the Modeless command, type DRO and press Enter on your keyboard to turn off Design Rule checking. Click OK to confirm switching to DRC Off mode. Batch verification is available for checking your work at the end regardless of whether DRC was on during routing or not. It is always a good idea to run these checks prior to generating films. ❶ Interactive Routing L9-1

5 Placement & Routing Lab 10 Manual Routing of High Speed Nets 121

6 Placement and Routing Lab 10: Manual Routing of High-Speed Nets PADS provides a scalable environment for routing high speed nets in interactive or automatic mode. Rules for high speed nets based on constraints like matched length, differential pairs and others are easy to set up. While routing is in progress, designers receive route length updates for critical and sensitive nets. PADS high speed routing tools are the force multiplier for increasing productivity on any complex PCB design. The Length Monitor can identify when a trace is within the defined length constraint by changing the color of the monitor. The color coding on the monitor also helps users to determine when they are close, within or have exceeded the length constraint defined on the net, while they are adding the trace data. High-speed routing commands and features give you control and flexibility when you route traces. Open Placed Board in PADS Router In this lab you will explore some of the high-speed features such as routing and tuning nets with accordions. Users can add accordions quickly based on default parameters or by re-defining the shape on the fly. You will practice Matched Length routing using the Length Monitor. Finally you will route differential pairs with via patterns. ❶ If it is not already running, start PADS Router by either clicking on the PADS Router icon located on the desktop or by selecting it from Start > Programs > Mentor Graphics PCB > PADS VX (32bit) > Layout & Routing > PADS Router and select File > Open. Select the Lesson26.pcb located at E:\PADS_ES_Evaluation\Lesson26 directory. Type Z<space>+27 and press Enter on your keyboard to enable visibility of Reference Designators on the Assembly Top layer. Manual Routing of High-Speed Nets L10-1

7 Placement & Routing Lab 11 Autorouting 121

8 Placement and Routing Lab 11: Autorouting When you autoroute a design in PADS, several autorouting operations are performed serially. You select the operations and the order in which they are performed. This is called an autorouting strategy. You also define the order in which the autorouter routes all components and net objects for each pass type. This is called the routing order. In this lab, you will experience the easy way that PADS helps you define your routing strategy, routing order and fanout rules for specific components. Open Placed Board in PADS Router ❶ If it is not already running, start PADS Router by clicking the PADS Router icon located on the desktop or by selecting it from the Start > Programs > Mentor Graphics PCB > PADS VX (32-bit) > Layout & Routing > PADS Router and select File > Open. Select the Lesson27.pcb located at E:\PADS_ES_Evaluation\Lesson27 directory. NOTE: Lesson27.pcb has manually (pre) routed critical nets and fanouts for ICs U8 and U100. Autorouter Strategy ❷ ❸ ❹ ❺ Select the Options button on the Standard toolbar or select Tools > Options from the menubar (or use the CTRL + Enter keyboard shortcut). All of these items will open the Options dialog. Click the second icon in the upper right corner of the display to change to full screen mode for this exercise Select the Routing > General page. Toggle through the different Routing Angles (Orthogonal, Diagonal, Any Angle). Enable the Diagonal option. ❻ Notice the Preview image changes to present a visual image of your selection. ❹ ❶ ❺ ❷ ❻ ❸ Autorouting L11-1

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