Allegro Free Viewer 15.0

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Allegro Free Viewer 15.0

• Installation
• Download from http//www.cadence.com/products/si_p
  k_bd/downloads/allegroviewers/index.aspx
• Opening Files
• Allegro opens PCB files with a .brd extension
• Simply select File-gtOpen and navigate to the
  board file that you want to look at

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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

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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

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Allegro Free Viewer 15.0

• Setting up the view
• Next, we need to clear the screen of the
  last-saved view settings
• Select Display-gtColor/Visibility
• Set Global Visibility to All Invisible and hit
  apply

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Allegro Free Viewer 15.0

• Select Display-gtColor Visibility and set to All
  Invisible

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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

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Allegro Free Viewer 15.0

• Turn on the listed Geometry layers

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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

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Allegro Free Viewer 15.0

• Turn on the listed Stack-Up layers

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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

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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

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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)

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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

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Allegro Free Viewer 15.0

• Finding Nets
• Show Element will bring up an information window,
  zoom to the net, and highlight it

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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

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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

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Allegro Free Viewer 15.0

• Hilight Color
• You can change either the Temporary (Show
  Element) or Permanent (Highlight) colors
• Again select Display-gt 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

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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

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Allegro Free Viewer 15.0
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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-gtColor/Visibility, then
  the Display Group and turn Shadow mode On,
  check the box to Dim active layer and hit
  Apply

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Allegro Free Viewer 15.0
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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

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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

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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.

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Allegro Free Viewer 15.0