Overview
NetBom has a voltage detection system that uses pattern recognition to determine voltage values for nets and parts. Given that voltage naming conventions change frequently and vary based on customer and need, this system has been expanded to allow for full customization.
The matching rules are small or large sets of regular expressions that are executed in sorted sequences to find the correct voltages based on the naming conventions.
Users can also manually map voltages using a separate configuration outlined below for nets with a voltage that cannot be determined by a pattern match.
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For customers that want assistance with creating a custom voltage matching ruleset, this service is available. |
Net Voltage Pattern Matching
The pattern net voltage pattern matching is useful in cases where nets carry a voltage that is encoded in the net name. These patterns and instructions live in a file that is pointed to by the CSet VOLTAGE_MATCH_OVERRIDE and can be accessed from the NetBom configuration menu in the main NetBom window (see screenshots in the section below).
Rule Types
The voltage matching rules come in four types.
EXCLUDE - these rules mark the test as no voltage
GROUND - these rules mark the test as ground
NEGATIVE - these rules mark the test as a negative voltage
POSITIVE - these rules mark the test as a positive voltage
Each of these sets is run in sequence in the order listed above, with each set being sorted by rule length, and the rules executed in order of shortest to longest.
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If a net is manually mapped (using the mapping feature described in the section below), it will not be run through the voltage pattern matching algorithm even if it has an encoded net name that otherwise would’ve been matched. |
How To Customize
To start, run any NetBom operation that generates a report. Once this is finished, there will be a file in the output directory called default_volt_match_strings.txt. This will contain all the NetBom default voltage matching rules and is a good place to start making changes.
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The negative and positive rules will require one or two regex groups. This allows for voltages that carry a decimal. The first group is the voltage value to the left of the decimal, and the second group is the voltage value to the right of the decimal.
Manual Net Voltage Mapping
NetBom provides a configuration that will allow the user to map specific nets to specific voltages.
This manual mapping configuration lives inside a file that is pointed to by the CSet NET_VOLTAGE_MAPPING_FILE.
This is useful for designs that have nets that carry a voltage but the voltage is not encoded in the net name, so the Voltage Matching feature won’t be able to determine the voltage automatically.
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All nets that are manually mapped will be excluded from the pattern matching algorithm even if they would have otherwise been matched by one of the configured patterns. |
Format:
The format of the manual net voltage mapping file is very simple. It takes a net name pattern on the left and a voltage on the right, with an equals sign in the middle. The pattern will be executed as a case-insensitive exact match using regular expression notation.
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# format: NET_NAME=VOLTAGE
Example Usage:
CD_PA_VDD_CH=1.75V # will only match the net name exactly
DC_MPA_VDD.*=1.75V # will match any net name that starts with DC_MPA_VDD |
Configuration GUI Access
To view and edit the CSets mentioned above, navigate to Configure NetBom Settings->Configure Power & Voltage Rules from the main NetBom window. See the screenshot below.
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To edit the voltage pattern matching, see the red box in the gui popup below. To edit the manual voltage mapping, see the green box below.
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