Netlist Extraction (Part 1)

Up to this point all the effort has been to make the settings required for CAM350 to operate on the database. But before that can happen there are 2 more operations that must be performed on the database itself to prepare it for netlist extraction.

1. If there are areas of Poured Copper on the outer layers you may need to Convert Draws to Raster Polygons before a netlist can be successfully extracted.

First, try extracting the netlist without taking this step. The file has been saved to this point so skip to step 2 (convert draws to flashes) and then go on to extract the netlist. 
If netlist extraction is not successful reload the last saved version and Convert Draws to Raster Polygons as follows:

Select Utilities/Polygon Conversion > Draw To Raster Poly.

The Command Status prompts for a selection or window.

Do Not use a window to define the area to be processed if that area will also include traces. Only areas of copper flood should be selected. Objects will become highlighted as they are selected. If there are a large number of polygons, consider creating a separate layer for just the copper. Perform the conversion then copy the copper to the correct associated layer.


When the instances of polygon have been selected, click the RMB to begin the conversion process. A dialog box will appear. Click OK with the LMB to start conversion.

When the Command Status display prompts for a selection again the process is complete.

Terminate the command by clicking the RMB.


The next blog post will show a demonstration of the Draw to Raster Poly command.

Aligning Layers (Layer-to-Layer Alignment) - LAB

The layers and drills have been deliberately offset.


First we’ll align layer 1 with layer 2 using Edit/Layers > Align.


Turn off all but layers 1 and 2. 
(These layers should be CAM_DemoL1.PHO and CAM_DemoL2.PHO respectively).

• CAM_DemoNC3-4.DNote the instructions in the Command Status area of the Status Bar that will assist you in stepping through this procedure.

•  Make sure the “Snap to Object” (“Z”) button is pressed on the Status Bar.

Select the lower left mounting hole on layer 2. 

Click on the object using the LMB (Left mouse button) then “Commit” to this selection by clicking the RMB (right mouse button.).

• Note how the “Page Up” and “Page Down” keys can be used to increase or decrease the “pick” area of the cursor.

• Note that layers may be freely turned on or off to facilitate selection.

Select the complimentary object on the layer to be aligned with the LMB then commit to the object with the RMB.

• Note the fact that this procedure cannot be undone. 

A warning message allows an opportunity to abort if necessary.


Clicking the RMB a second time completes the operation aligning the two layers.

Aligning Layers (Layer-to-Layer Alignment) - Video

Here's a demonstration of the Layer-to-Layer Alignment procedure:

Aligning Layers (Layer-to-Layer Alignment)

Once loaded, the layers and drills may not be aligned.
(For this demonstration they have been deliberately offset).

Before any meaningful analysis can be done all the elements must be aligned to each other and also to the origin.


Note: 
It is essential that the origin of the CAM350 elements match the origin of PCB design file.




Alignment can be performed in two ways. 
The first, Edit/Layers > Align…

Follow the directions that will appear in the Command Status area of the Status Bar.

Select the point on the “reference layer” to which the “offset layer” layer will be aligned. This object must be present on both layers. 

Choose a mounting hole or other prominent feature.

Note that layers may be freely turned on or off to facilitate selection.

Make sure the “Snap to Object” button is pressed.

Click on the object using the LMB (Left mouse button) then “Commit” to this selection by clicking the RMB (right mouse button.).

The Command Status changes to:

Select the complimentary object on the layer to be aligned with the LMB then commit to the object with the RMB.

Clicking the RMB a second time completes the operation aligning the two

layers.

Note that this procedure cannot be undone. 

A warning message allows an opportunity to abort if necessary.

Layer Table and Defining Layers - LAB

Use the Tables pull down menu or the “y” hotkey to access the Layer Table. 


Refer to the layer definitions in the Readme text file in the Gerber file directory for the correct layer Types.


Assign Draw and Flash colors. Then exit the menu.




Experiment

• Can you figure out what the file types are by looking at the layers?

• What happens to the colors in the Layer Bar?

• Can you change the layer names?

• Turn off all but two layers. Set one of the layers to Ref using the status button. 

           What happens when you redraw the display? 

• What happens if you try to select an object on the REF layer? 

           (Use Edit/Move or Copy as a selection device).

Layer Table and Defining Layers - Video

Here is a demonstration of the Layer Table setup procedure:

Layer Table and Defining Layers

Use the Tables pull down menu or the “y” hotkey to access the Layer Table.

The layer table is used to set the layer Type, and assign Draw and Flash colors. 
It can also be used to set the Active layer (the layer that remains on when all others are turned off) and the Top layer (the layer that redraws last and therefore appears “on top” in the screen display). 


The Data column indicates whether or not the layer contains any data.


(Note that the layer numbers correspond to the numbers in the layer bar.)

Layer types are selected from a pull down menu that is accessed from a cell in Type

column of the layer’s row.

Select the appropriate layer definition from the available options.

Note: 

Whether a plane is positive or negative has nothing to do with its electrical characteristics

but with whether the photo file represents a positive or negative image. “Positive Plane”

layers are processed the same as “Internal” layers

Colors are selected from a chart that pops up by clicking the Draw or Flash cells. 

Color selection is purely a matter of user choice. Try to select familiar draw colors that will help you recognize layers on sight. Choose a different (preferably dark) color for flashes.

In addition to the ability to turn layers On and Off the Layer Table can set a layer to “Ref”

(for reference). In this condition objects on a layer can be viewed but can not be selected.

A video demonstrating Layer Table and Defining Layers will be posted on the next blog post.

Ordering Layers - LAB

From the Edit pull down menu, select Layers/Reorder.

(Note the layer order as it appears in the Active Layer pulldown window.)

On the Reorder Layers popup menu, click on a line item and drag it to a new location in the layer order.

When all layers have been placed in the desired order, click on the Renumber button.

Exit by clicking on the OK button with the LMB.

(Note the layer order as it now appears in the Active Layer pulldown
window.)

Ordering Layers - Video

Here's how ordering layers is done in CAM350:

Ordering Layers

Each Gerber file that has been imported represents a “Layer” of the design. 


If we could see a cross section of the design we would see that each of these layers occupies a unique physical space from top to bottom. Putting the layers in a specific order is more of a user choice issue than an operational requirement. In fact, the order means nothing. It’s simply conducive to the sanity of the user.


From the Edit pull down menu, select Layers/Reorder.

When the Reorder Layers popup menu appears, 

click on a line item and drag it to a new location in the layer order.

Before Reorder

After Reorder

When all layers have been placed in the desired order, click on the Renumber button.

This will assign a new layer number that corresponds to the numbers on the layer bar.

Exit this menu by clicking on the OK button with the LMB.

The next blog will show a demonstration of the Layer Reordering procedure.

Importing Gerber and Drill Data - LAB

Use File/New to begin a new CAM350 session.

Select File/Import/Auto Import and set a path to the PCB2CAM350/

Gerber directory.

Set the button for Metric, then select Finish. 

Cam350 will automatically select and load the Gerber and NC drill files.

During the loading process a message will pop up warning of “Unassigned Tools. 

This concerns drill sizes which have not yet been set and is normalbehavior.

Note: Because this demonstration board has Blind and Buried vias the

             message pops up 3 times. Once for each drill set.

Experiments:

• What happens when you load the files with set the button set to English?

• What happens when you select Next instead of Finish?

Make sure the Gerber and Drill files are loaded correctly before proceeding.

Use the Settings/Units pull down menu and select Metric.

Use the File/Save As command at this point to open a new CAM350 database for this design. Set the path to your practice area and assign the file a unique name (i.e. don’t use the same name as the Demo files).

Use the CAM_Demo_Offset.CAM file as a reference if you have any questions.

Note: the dot “CAM” file extension denotes a native CAM350 formatted file.

            CAM350 files are Opened using File/Open.

Importing Gerber and Drill Data - Video

Here's how to import gerber and drill data using CAM350:

Importing Gerber and Drill Data

Use File/New to begin a new CAM350 session.

Then, select File/Import/Auto Import. 

Set a path to the directory that contains the Gerber and NC Drill data. 

Select the appropriate button for English or Metric, then select Finish. 

Cam350 will automatically select and load the Gerber and NC drill files 

(selecting Next allows the user to select the files that will be loaded).

If you’re a PowerPCB user you will see a pop up warning of “Unassigned Tools.

This concerns drill sizes which have not yet been set and is normal behavior.

A video tutorial to show this process will be posted on the next blog.

Subscribe to this blog and learn more about using CAM350 for PCB Designers.

Creating an IPC-D-356 Netlist - Video Tutotial

Here's a video on how to create an IPC-D-356 Netlist in CAM350:

Creating an IPC-D-356 Netlist

Verification of photo plots to the original design database is made possible by an IPC-D-356 Netlist. This type of netlist consists of connection information in an ordinate format – or a virtual 3 dimensional description of any net. 

Take a look at the following examples of netlist formats:

A simple netlist, such as might be generated by typical schematic capture software consists only of part/pin connection references.

Schematic Netlist:

*SIGNAL* NET_1
U1.1 U2.1


The same IPC-D-356 netlist connection generated from the CAD database by CAM350 would look like this:

CAD Data IPC Netlist:

317NET_1 VIA MD 500PA00X+ 2700Y+ 2000X1000Y S0
317NET_1 VIA MD 500PA00X+ 13400Y+ 2000X1000Y S0
327NET_1 U1 -1 A01X+ 2690Y+ 4550X 600Y2100 S2
327NET_1 U2 -1 A01X+ 13390Y+ 4550X 600Y2100 S2


And the same extracted net from the fabrication data by CAM350 would look like this:

Extracted Netlist:

317$Net0 VIA MD 500PA00X+ 2700Y+ 2000X1000Y S0
317$Net0 VIA MD 500PA00X+ 13400Y+ 2000X1000Y S0
327$Net0 VIA A01X+ 13390Y+ 4550X 600Y2100 S2
327$Net0 VIA A01X+ 13400Y+ 3000X 150Y S2
327$Net0 VIA A01X+ 2690Y+ 4550X 600Y2100 S2
327$Net0 VIA A01X+ 2700Y+ 3000X 150Y S2


Whether you can read this or not doesn’t matter, that’s what the software’s for.


CAM350 uses the PCB design database (as opposed to Gerber and NC drill data) to produce the reference IPC-D-356 netlist to which the fabrication materials will be compared.

Begin by opening a new session of CAM350.

From the File pull down menu, import CAD Data and select the appropriate CAD format.

Set a path to the ASCII file and Open it.

Numerous queries and warnings will pop up. For the purpose of creating the IPC-D-356 netlist, it’s not necessary to Extract Polygons for net checking.

…and you can acknowledge the warnings that follow.

Once the ASCII file has loaded, Export the IPC-D-356 netlist:

From the File/Export/Netlist select the IPC-D-356 option.

Click OK with the LMB, set a path and filename for the netlist and Save it.

There is no need to save the imported ASCII file once the IPC-D-356 netlist has been saved.

CAM350 User Interface

The CAM350 Window consists of a:

• Menu Bar
• Tool Bar
• Layer Bar
• Working Area
• Status Bar 
• and “Panorama” window pane.

The Toolbar, Layer Bar, Status Bar and Panorama Windows are enabled from the View Pull down menu.

Other viewing functions include: Window, (Zoom) All, Redraw, (Zoom) In and Out, and Pan

functions may also be accessed from the View menu. (Pan isn’t a pan in the true sense – it re-centers the view at the current cursor location).

Note that to the right of each of these keys is a “hotkey” that may alternately be used to perform the function.

The other pull-down menu options will be discussed in order of relevance as we progress through this tutorial.

The appearance of the Toolbar will vary according to the function being performed but there are always three pull down selections available.

From left to right they are:

1. The Grid setting. 

    This pull down options lets the user select the Grid-Snap spacing.

2. The second pull down is the Active D-Code selector. 

     It has no practical application in this context.

3. The Active Layer pull down selection sets the “Active Layer”. 

    The active layer is noted by a red box in the cell (No. 1) and indicates the layer that will 

    not be turned off by an All Off command. A blue box (No.16) indicates the layer that 

    appears “on top” of the display.

Note that the pull down selector has the full name of the photo plot or NC

Drill file associated with a particular layer number.

The Status Bar has 3 parts:

1. The left section (0,0:0,0) is readout of the cursor X-Y position in project units.

2. The center area (Select Command) shows the status of any command that may be active.

3. The right area consists of 5 “buttons”…>

which toggle their functions as follows:

“Z” causes the cursor to snap to an object. In this mode the cursor will snap to the center of a “Flash” or the end of a “Draw”.

“S” enables the cursor to snap to the grid (as set by the Snap pull down selector from the Toolbar pull down).

“V” toggles the grid display on and off.

The “T” and “H” have no relevance to this tutorial.

The status of these buttons can be changed either by pressing the corresponding keyboard key or by placing the cursor over the button and “clicking” the Left Mouse Button (LMB).



The Panorama Bar shows a “Thumbnail” picture of the viewing area referenced to the design extents in a “Window Pane” that may be moved around in the work area.

CAM350 LAB for PCB Designers

All the materials you need to perform the same operations as in the companion tutorial are provided to allow you try out the features that have been demonstrated (provided you  have CAM350). 


They consist of: 

• PowerPCB files: A PCB file of the demo board (not used but are provided for reference). 

• An ASCII file (can be used to create an IPC-D-356 netlist). 

• An IPC-D-356 netlistGerber and NC Drill files 

• CAM350 files: Some of these files will be used to try out certain features of CAM350. Others, as a reference for comparing your results. 

It is suggested that you create a new directory on your local drive where these materials can be copied from the CD.

CAM350 for PCB Designers - Overview

CAM350 is a multi-use tool for printed circuit board design and fabrication. It can be used to verify CAM materials that have been created by other PCB design tools such as PowerPCB or Cadence. It can be used to prepare those same materials for various processes such as step and repeat, panelization or adjusting feature sizes to compensate for fabrication variables. It can even be used to design a PCB board from the ground up or reverse engineer a PCB design from existing photo plots.


This tutorial will focus on the first of these applications – using CAM350 to verify Gerber and NC Drill data that has been created by another PCB design tool.


Now, all PCB design tools have DRC (design rule check) utilities to verify connectivity and spacing rules. But these utilities only check the rules against the Design Database. CAM350 has the ability to check the design database against the actual materials that will be used to manufacture the PCB. This adds an extra layer of protection from errors that can be
introduced either inadvertently by incorrect settings in the utility used to generate the fabrication materials, or the potential inability of the design software to detect certain errors.


Additionally, we’ll look at the output capabilities of CAM350 to create check plots, Gerber and NC files, and a “smart” ODB++** database that is compatible with Valor-Genesis software.


The necessary steps will typically be explained with text and graphics. However, most operations will also be demonstrated with “live action” using on-screen digital video media.


You do not need any special software installed to use this tutorial.


Materials for this tutorial were created using PowerPCB V5.0.1 and CAM350 V7.5.2.


* CAM350 is a registered trademark of Downstream Technologies
** ODB++ is the property of Valor Computerized Systems
# PowerPCB is a registered trademark of Mentor Graphics

Release Highlights for CAM350 Product Version 10.2

Introduction


CAM350 Version 10.2.2 is a support release for CAM350.  CAM350 10.2.2 includes support for  Microsoft Windows 7 and Mentor PADS Layout version 9.2.  Other CAM350 updates include resolutions for customer reported problems concerning ODB++ support for offset pads and flip panels, mill tabs in route arcs and mill route support for flipped images. 


 CAM350 10.2 includes Gerber import improvements for polygon self intersection analysis and DRC analysis accuracy updates for polygon outlines with arcs. 


CAM350 Version 10.1 is a support release for CAM350.  CAM350 10.1 includes performance improvements and memory usage improvements over previous releases of CAM350. Areas of improved performance include Gerber import and ODB++ import.  Optimization for memory usage is delivered in CAM350 10.1 for all polygon analysis, which means that larger more complex layers of polygons can now be processed for commands such as Netlist Extract and Gerber Import. CAM350 10.1 also delivers over 50 important customer reported defect resolutions. 


CAM350 Version 10.0 introduced significant new functionality, including reading and writing BluePrintPCB files, new graphics user interface, a project explorer bar, flip panel support, design compare, Expedition cross probing, and various enhancements. 

New Functionality


The following functional enhancements are contained in CAM350 Version 10.1

• 9 Gerber Import and Export Improvements 
• 9 ODB++ Import Improvements 
• 9 Netlist Extract Updates 
• 9 PADS Import Updates 

Details


Gerber Import and Export Improvements – The File > Import > Gerber Data command has been updated for CAM350 V10.2 to report illegal self intersecting polygons and prompt the user with the option to repair.  


The File > Import > Gerber Data command has been updated for CAM350 V10.1 to include faster polygon processing.  Certain CAD systems generate so-called cutline polygons that are used for efficient flooding and display.  CAM350 reduces these complex shapes into simple outlines with circular or polygonal voids.  The process to analyze the cutline polygons has been optimized.  For certain Gerber designs, import times can improve by up to a factor of 20 times.  This optimization will affect many Mentor Graphics designs. 



The File > Import > Gerber Data and File > Export > Gerber Data commands have been updated to pass arcs in polygon outlines as true arcs, rather than as segmented chords.
This update allows for more accurate Gerber data in CAM350 and allows for smaller Gerber files on export from CAM350. 


ODB++ Import Improvements – The File > Import > ODB++ command has been updated for CAM350 V10.1.  The ODB++ data transfer format is an important standard for the PCB fabrication industry. For CAM350 V10.1, the ODB++ import performance has been improved by up to a factor of 10 times for large designs. The ODB++ import command is also updated for CAM350 V10.1 to support stacked blind and buried vias. Netlist Extract Updates – For CAM350 V10.1, the Utilities > Netlist Extract command has been updated to utilize memory more effectively. Specifically, for large designs, the analysis of complex layers in previous releases of CAM350 could exceed the standard 2 gigabyte limit for processes on Windows 32 bit operating systems.  Parallel programming for layer analysis is now used in CAM350 V10.1 to break through the 2 gigabyte limit.  For large designs, the connectivity analysis for complex layers is performed in separate 2 gigabytes memory pools, separate from the main CAM350 process.  The parallel programming techniques are invoked based on the quantity of data being analyzed. Additionally for CAM350 V10.1, the Utilities > Netlist Extract command has been updated to support complete connectivity analysis of plated drill slots, plated mill slots and all plated mill routes.  The analysis of plated slots and mill routes now enables greater coverage of the final fabrication artwork.  


PADS Import Updates – The File > Import > CAD Data command has been updated to support PADS Layout Version 9.0.  New features include support for importing chamfered and rounded pads from PADS Layout decal definitions.  These new pad definitions coincide with ODB++ intrinsic aperture definitions.  The ODB++ standard names are used for these chamfered and rounded pads.  


Defect Fixes – Over 50 software corrections have been made to previously existing functionality, further improving upon CAM350’s quality and reliability.


Full details of the Release Highlights for CAM350 Product Version 10.2 can be obtained on this link.
http://www.downstreamtech.com/support/support-cam350/CAM350_10/CAM350_10.2.2ReleaseHighlights-Build401.pdf