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.

Layer Sets (for Blind and Buried Vias) - LAB

Select Tables/Layer Sets > Blind and Buried pull down menu option.


Click on the Thru Drill button and select CAM_DemoNC1-6.D from the Layer List window.


Change the Name entry to LyrSet_1-4.


Click on number “1” from the list with the LMB. 
Add CAM_DemoL1.PHO to the list. 
Do the same for numbers 2, 3, & 4 with CAM_DemoL2, L3 &, L4.PHO respectively.


Click on the Drill Data button with the LMB to pop up the layer list. 
Click on the appropriate layer with the LMB to andselect CAM_DemoNC1-4.D from the Layer List window.


Click the Add button with LMB to create a new layer set name.


Change the Name entry to LyrSet_3-4.


Click on number “1” from the list with the LMB. 
Add CAM_DemoL3.PHO to the list. 
Add CAM_DemoL4.PHO to number 2.


Click on the Drill Data button with the LMB to pop up the layer list. 
Click on the appropriate layer with the LMB to andselect CAM_DemoNC3-4.D from the Layer List window.


Save your work now using File/Save.

Layer Sets (for Blind and Buried Vias) - Video

Watch this video to view a demonstration of the Layer Set operation for Blind and Buried Vias:

Layer Sets (for Blind and Buried Vias)

When Blind and Buried vias are used in a design CAM350 must be instructed as to the relationships between the Drill Tables and the layers they are associated with. A Layer Set Table is used for this purpose.


The layer set table is accessed from the Tables/Layer Sets > Blind and Buried pull down menu option.

Click on the Thru Drill button to pop up a Layer List window.


Select the layer associated with the final stage (through) drill using the LMB 
(in this case “CAM_DemoNC1-6.D”).

Set up the table for the fist (blind) layer set as follows:
1. Change the Name entry to reflect the layer set (1-4)


2. Click on a number from the list with the LMB. A Layer List window will pop up. 
     Click on a layer from the list that is to be added in the numbered layer position. 
     In the following example we can see that layers 1 and two have already been selected.    
     Adding CAM_DemoL4.PHO will complete the Blind layer set.

3. The drill data for this layer set is added in the same manner as for the thru drill. 
     Click on the Drill Data button with the LMB to pop up the layer list. 
     Click on the appropriate layer with the LMB to select it .

Set up the table for the second (buried) layer set as follows:
1. Change the Name entry to reflect the layer set (3-4)


2. Click on a number from the list with the LMB. A Layer List window will pop up. 
     Click on a layer from the list that is to be added in the numbered layer position. 
     In the following example we can see that layers 3 has already been selected. 
     Adding CAM_DemoL4.PHO will complete the Buried layer set.

3. The drill data for this layer set is added in the same manner as for the thru drill. 
     Click on the Drill Data button with the LMB to pop up the layer list. 
     Click on the appropriate layer with the LMB to select it .

This completes the Layer Set setup.

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 - LAB

The utility CAM350 uses to produce the IPC-D-356 netlist is an installation option. 


If you haven’t purchased the CAM350 CAD to IPC option you will not be able to perform this step. Instead, use the CAM_Demo_IPC.Net file provided in the Lab demonstration materials. 


Open a new session of CAM350. 


Using File/ Import > CAD Data select the PowerPCB CAD format. 


Set a path to Cam_Demo.ASC and Open it. 
(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 using the File/Export > Netlist > IPC-D-356 option. 


Set a path to your practice directory, assign a 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.

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 LAB

Open CAM350 using the icon on your desktop
or Start > Programs > CAM350 V7.5.

Lab sections will often direct your attention to areas in CAM350 window so the following is a review of the User interface and the names that will be referred to.

The Status Bar consists of the following components:

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

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

• 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 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.