Net Group Setup

Using the Net method, you can add nets into a net group in three different ways: Set Net Group Contents, Select Nets From Drawing, and Select Net List. A net group can be saved into a net text DB file (*.txt) or an existing net text DB file (*.txt) can be imported.

• Add Groups: To add net groups, specify the number. New rows are added to the table.
• Filter Type: There are two methods to assign a net group type – by selecting nets (Net) and by selecting a predefined text DB file (*.text). Using the Net method, you can add nets into a net group in three different ways: Set Net Group Contents, Select Nets From Drawing, and Select Net List. A net group can be saved into a net text DB file (*.text) or an existing net text DB file (*.text) can be imported.
• Set Net Group Contents: Select nets using key word and string filter types: Prefix, Mid-String and Suffix. After entering a key word and choosing a string filter type, click Add String to look up and find Net names that contain the strings used in the filter. Various types of filtering combination options helps you to make accurate filtering. Upon clicking All Net, the program selects all net names.
  • Add And Combination: Add this string to selected string with and combination.
  • Add Exception String: Select net names which do not contain the filter string.
  • Add Exception String: Add this string to selected string with exception combination.
• Select Nets From Drawing: Select nets from a graphical display of design. This is a useful option when net names are unknown but nets can be located on a drawing.

  
  
  Figure 1.

  Upon selecting Net Color in PollEx PCB, it will be much easier to distinguish nets from all routing. For more information about setting net colors, refer to the PollEx PCB manual.
• Selected Net List: Select nets from a list. It also highlights nets that match with a search string by entering a part of net. Highlighted nets can be added to the Selected Net list by clicking Add to List.
• Save To Net DB File: Net group data created by the methods described above can be saved into a text format net DB file.
• Select Net DB File: A net DB file can also be imported from the DB list.
• Delete Selected Net Group Item: Unnecessary net groups can be removed by choosing a Delete Selected Net Group Item option.
• Default DB Path Change in Group: When you define net groups, they are saved into a DB file. A default DB file path can be assigned or changed by selecting a folder from the Net Group DB Path dialog.
• Import Excel: Assign required net groups automatically by using an excel file that describes the pre-defined net group search condition. The default excel file is in C:\ProgramData\altair\PollEx\2021.2\Data\Excel-Report.
• Import from net class definition: Define net groups automatically by using net classes information.
• Composite Net: Composite-Nets are combined nets through passive devices. PollEx DFE can merge two or multiple single nets into composite net. The PollEx PCB can make composite net also, but DFE does not refer composite result from PollEx PCB.
• Edit Composite Net Structure.There are two methods to assign passive composite component: using a part of component reference name string and using predefined Component Group.
  • By string of reference name: Assign passive composite components using a portion of component reference name. For multi pin components, you can use the Array Resistor or Filter option. For multi-pin components which have an even number of pin counts, the DFE automatically makes pin paring using relative position of each pin. The two pins which have long pin pitch will be pared.

    
    
    Figure 2. Array component pin paring

    • Resistor:
    • Capacitor:
    • Inductor:
    • 2Pin Component:
    • Array Resistor: For 8pin array component only.
    • Filter: For any component which has even number of pin count.
  • By Component Group name: You can assign passive composite components using Component Group name.
    • Group Name:
    • Filter Group Name: For any component which has even number of pin count.
• Exclude Differential Pair Net: You can exclude passive components which are used for parallel terminator of differential pair net.
  • Differential Pair Net Group: Define differential pair net group.
  • Define Differential Net Pairs: Define pin pair information of differential pair net using net name string filter. As an example, in the figure below, DRAM_CLK and DRAM_CLK# nets are paired together.
• Exception
  • Exclude Net Group: You can exclude some net group by net group name using this option. Normally, the Power and Ground net should be excluded.
  • Exclude Nets by portion of net name string: You can exclude some nets by name string filter using this option.
  • Exclude Component Group: You can exclude some component group by component group name using this option. Normally, the Test Point can be excluded.
• Show Composite Net: Review the result of Composite Net creation.
• Define Differential Net pairs: Define pin pair information of differential pair net using net name string filter. The flow to define pair information is the same as the ⓒDefine Differential Net pairs sub-menu of Edit Composite Net Structure menu as described above and the pairing information will be synchronized with that menu.