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Components on a board are often placed per their functional group and hence their reference designators are all jumbled up. It is a common practice to rename reference designators before sending out the design data to manufacturers. Reference designator renumbering is a process for renaming the reference designators on the board so that it is easier to locate components on the boards during assembly, test, and troubleshooting.
There are several industry standards that represent reference designators in different formats, like IEC 60617, IEEE 200-1975, and ASME Y14.44-2008. Design houses may also use formats that do not comply with the standards. To ensure reference designators are accurate before generating manufacturing files, you can rename reference designators to a specific standard/format using a batch program reftxt, which is available with the Cadence® Allegro® layout editors. This batch command uses a text file that contains a list of reference designators in two columns. The first column shows the existing reference designators and the second column shows the new/renamed reference designators. The command renames any number and type of reference designators simultaneously and applies new ones with any number of characters.
To create a list of the existing reference designators, enter extract_ui command in the Command window of the layout editor. In the Extract UI form, under the Data Fields tab, select Database View as Component. From the Available Fields section, select REFDES to move it to the right window. You can select REFDES_SORT instead if you want a sorted list of reference designators. Save the settings in text file refdes.txt and close the Extract UI form.
Open refdes.txt in an ASCII text editor or Excel. Copy the first column and paste it into a second column. Specify the new REFDES values in the second column and save the file as refdes_ch.txt.
To run the reftxt command, open command prompt and change directory to the location where the input board design and a was/is list of reference designators are located. Use the following command syntax to run the command:
reftxt rename_file design_name [output_name]
An example is shown in the following figure:
The output design file name is optional. If not specified, then the command uses the input design name to overwrite the changes. The reference designators will be renamed in the output board design as specified in refdes_ch.txt file and a reftxt.log file is created that contains errors, warnings, and successful reference designators names that were changed.