pcb-rnd knowledge pool

 

DRC: links to doc and DRC check scripts

Idrc by Tibor 'Igor2' Palinkas on 2021-05-20	Tags: index, drc, query
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Abstract: As part of the nlnet NGI0 funding, pcb-rnd got a full DRC (Design Rule Checker) rewrite in 2020. The new DRC system is extremely flexible as it is scriptable using the query language. This article is a collection of links to resources for those who are interested in advanced use of the new DRC system.

 

Documentation

• drc user manual : how to configure and run DRC, how to develop simple DRC rules (tutorial)
• query user manual : pcb-rnd's flexible query language:
  • language syntax
  • builtin functions
  • tutorial on writing query expressions
  • Interactive/GUI interface: Select menu, Advanced search and select; this provides a GUI for building and testing query expressions
• keepout/courtyard implementation details (serves as an example/howto for developing DRC scripts)

DRC scripts

• Stock scripts shipped with pcb-rnd (largely the same functionality that the old DRC system had):
  • stock rules : list and short description of the stock DRC rules shipped with pcb-rnd
  • New: keepout/courtyard - checks for mechanical overlap of parts
• Contributed scripts, available for download
  • zone based clearance rules : draw polygons on a dedicated doc layer to mark regions of the board where different clearance applies. Useful e.g. for high voltage areas.
  • ustrip : check microstrip traces for estimated impedance along the full length using rule-of-thumb formulas
  • floating : find floating copper objects that are not connected to any network
  • per net clearance : ensure copper objects forming a net have the sufficient, net defined clearance
  • wire direction : check for lines to be octilinear, rectilinear, strictly horizontal or vertical if a layer requires that
  • net lengths : check for absolute and relative network length (e.g. length matched pairs)
  • net via num : check for number of vias on a net (for limited or controlled parasitics)
  • net trace width : ensure trace width defined in net attribute
• A per typical use case breakdown of scripts is also available.

Special thanks to nlnet for supporting development of the new DRC system and related documentation as part of the NGI0 PET fund.