Allegro Free Viewer 15.0

1. Allegro Free Viewer 15.0 • Installation • Download from http://www.cadence.com/products/si_pk_bd/downloads/allegroviewers/index.aspx • Opening Files • Allegro opens PCB files with a .brd extension • Simply select File->Open and navigate to the board file that you want to look at

2. Allegro Free Viewer 15.0 • Setting up the view • Always best to start with a clean slate • This example sets up the board for viewing from the top side • Typically, start by zooming to fit the board to the window • Also probably want to turn off the grid dots if they are on

3. Allegro Free Viewer 15.0 • Click zoom-fit or hit F9 to see the whole board • Click on grid toggle, or hit Shift-F9 to toggle grid off

4. Allegro Free Viewer 15.0 • Setting up the view • Next, we need to clear the screen of the last-saved view settings • Select Display->Color/Visibility • Set Global Visibility to “All Invisible” and hit apply

5. Allegro Free Viewer 15.0 • Select Display->Color Visibility and set to “All Invisible”

6. Allegro Free Viewer 15.0 • Setting up the view • Select Group = Geometry and scroll down to check boxes next to • “Outline” under Board Geometry • “Silkscreen_Top” under Board Geometry • “Silkscreen_Top” under Package Geometry • “Assembly_Top” under Package Geometry • Then select “Apply”

7. Allegro Free Viewer 15.0 • Turn on the listed Geometry layers

8. Allegro Free Viewer 15.0 • Setting up the view • Select Group = Stack-Up and scroll down to check boxes next to • “Top” under Pin • “Top” under Via • “Top” under Etch • Then select “Apply”

9. Allegro Free Viewer 15.0 • Turn on the listed Stack-Up layers

10. Allegro Free Viewer 15.0 • Layers • Allegro board files consist of many “layers” • There are, for example, “etch” layers which are the actual copper connections • There are also soldermask and silkscreen layers which correspond to the green outer coating and white labeling respectively • And, there are other information-only layers that show dimensions, part outlines, etc. • You will typically be focusing on the etch layers

11. Allegro Free Viewer 15.0 • Layers • There is a quicker way to set visibility for etch layers • On the right hand side of the window there is a tab for “Visibility” • You can use this to turn on and off signal and plane layers and the vias and device pads for those layers

12. Allegro Free Viewer 15.0 • Finding Nets • You will normally want to look at a signal or set of signals, referred to in Allegro as “nets” • To find a net, you can highlight it • There are two ways to highlight • Show Element (Temporary) • Hilight (Must Dehilight to turn off)

13. Allegro Free Viewer 15.0 • Finding Nets • After selecting either “Show Element” or “Hilight”, select the Find tab on the right • Under “Find By Name” type in the name of the net and hit enter. • You may use * as a wildcard if you are uncertain of the full net name or if you want to highlight a group of nets

14. Allegro Free Viewer 15.0 • Finding Nets • Show Element will bring up an information window, zoom to the net, and highlight it

15. Allegro Free Viewer 15.0 • Finding Nets • Highlight will simply zoom to the net, and highlight it • You must use “De-highlight” to turn off the net highlighting

16. Allegro Free Viewer 15.0 • Finding a group of nets • As mentioned, you can find multiple nets at once using a * as a wild-card • For example, most clock signals include “CLK” as part of the net name. • To find all clocks that have “CLK” in the net name, you can type in “*clk*” in the find filter • This will highlight all such nets

17. Allegro Free Viewer 15.0 • Hilight Color • You can change either the Temporary (Show Element) or Permanent (Highlight) colors • Again select “Display-> Color/Visibility” then change Group to “Display” • Click on the color you want from the palette and select the colored box next to the appropriate highlight type

18. Allegro Free Viewer 15.0 • Finding and following long nets • Long nets that span a large section of the board will be hard to see when Allegro zooms to fit the net • After highlighting one of these nets, you will need to zoom in manually • Look in the lower right corner and you will see a miniature display of the board outline along with the highlighted net. • Click and drag a box around the net in this window to zoom in on it • Then click on “Zoom Points” to allow you to draw a box around the highlighted item in the main window and zoom in further

19. Allegro Free Viewer 15.0

20. Allegro Free Viewer 15.0 • Finding and following long nets • After you have zoomed in on the net you will want to turn on all signal etch layers and shadow mode to make the net stand out • First, go back to the Visibility tab on the right and check the box under “Etch” and next to “Conductors” • Next, select “Display->Color/Visibility”, then the “Display” Group and turn Shadow mode “On”, check the box to “Dim active layer” and hit “Apply”

21. Allegro Free Viewer 15.0

22. Allegro Free Viewer 15.0 • Finding and following long nets • To follow the net, or to pan in general, press and hold the middle mouse button and drag your cursor in the main viewing window • In this way you can follow the net where ever it goes

23. Allegro Free Viewer 15.0 • Finding etch length • If you need to know the length of a net or a part of a net, you can get that information from the window that appears when you use “Show Element” • If you use Show Element for a net, the window will list the entire net length

24. Allegro Free Viewer 15.0 • Finding etch length • If you want to find the length of a section of the net, you can get either Cline or Cline Segment lengths. • A Cline is any part of a net that routes on a single layer until it runs into a pin, via, or other feature. • A Cline segment is any part of a net that routes on a single layer until it runs into a bend, pin, via or other feature. Basically, any single straight segment. • This time, select Show Element, but instead, check the box for Cline or Cline Segment and the click on the segment you want to measure.

25. Allegro Free Viewer 15.0