Altair PollEx is said to be “ECAD Agnostic”, which means it can import PCB designs from every mayor ECAD vendor. Due to how some vendors handle their file formats, some configuration must be done to import designs. In this tutorial, the steps to correctly set up PollEx to import Cadence Allegro designs are shown.

1. Find the “Extract Utility” and the “Command” files

To import a design, PollEx needs access to the “Extract Utility” which is the “extracta.exe” file that you can find on the tools\bin folder on your allegro installation. For a case where Allegro is installed in the C:\ directory, the location is the following:

C:\Cadence\SPB_17.4\tools\bin

PollEx uses the "CDSROOT" environment variable to look for this file, verify it exists before proceding with the setup. If this variable doesn't exist it can be created or the path can be provided in PollEx settings as described in the next section.

PollEx also needs a Command File which allows PollEx to use the Extract Utility, this is found on the PollEx install directory. The case for a PollEx installation on the C:\ drive is the following:

C:\ProgramData\altair\PollEx\2023\Share

There are multiple command files in this folder, the ones needed for setup are the following:

• AllegroExpansion_ExtractCommandFile.txt (for Allegro versions bellow 16.3)
• AllegroExpansion_ExtractCommandFile163.txt (for Allegro versions above 16.3)

 

2. PollEx Setup

To setup PollEx we need to access the PollEx ECAD Settings which can be accessed from the menu bar as seen in the following image:

Figure 1 How to get to the Cadence Allegro Expansion Settings

Now, on the Cadence Allegro Expansion settings we need to toggle on the binary import and supply the path to the “extracta.exe” file and the control file.

Figure 2 Path setup for extracta.exe and control file

 

If the path to the "extracta.exe" file is left blank, PollEx will attempt to find it by using the environment variable "CDSROOT" which contains the install path of Cadence Allegro. Another way of setting this up would be for the user to create this environment variable if it doesn't exist.

 

Click “Ok” to save these settings and exit the settings window.

3. Import a binary (.brd) design.

From the menu bar, go to File > Import ECAD > Cadence Allegro Expansion, select “Allegro Binary File” and provide the path to the design file. Then click import.

Figure 3 Instructions to import a design file

4. Part Name Setup “Optional”

PollEx can use different information from the design file to name parts. If there’s a need to change the information used for part name this can be changed from the Cadence Allegro Settings (Figure 2) in the “Options” Tab.  

Figure 4 Define part name Setup

 

5. The Difference between Binary and ASCII formats

Cadence Allegro’s binary design files (.brd) can’t be visualized or imported by third party software. Cadence deals with this by giving the user an Extract Utility which is included with every installation, this file converts Allegro’s binary (.brd) to multiple text files (.txt) that contain ASCII data which can be imported by third party software.

The file structure of the ASCII files is shown in the following table:

 

Binary	ASCII
*.brd	*_Comp.txt
	*_CompPin.txt
	*_Geom.txt
	*_Lay.txt
	*_Net.txt
	*_PAD.txt