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What's Good About Allegro PCB Router Staggered Via Rules? See for yourself in 16.5!

Comments(0)Filed under: PCB Layout and routing, PCB design, Allegro PCB Editor, Allegro, PCB Editor, PCB, layout, global route, routing, SPB16.5, Allegro 16.5, via rules, staggered vias, vias

Just a quick blog today on a new 16.5 Allegro PCB Router enhancement for Staggered Via Rules.

The stagger gap value is defined by rules at the following levels:

  • PCB
  • Layer
  • Class
  • Net
  • Region

 

 

Option Descriptions:

on - turns the rule on.

off - turns the rule off (default)

min_gap - controls the minimum distance between consecutive vias in the pattern.
If min_gap is not specified, a proper samenet bbvia/microvia to samenet bbvia/microvia clearance rule in effect controls the distance. An assigned negative value means no restricted min distance between consecutive vias in the pattern

max_gap - controls the maximum distance between consecutive vias in the pattern. If max_gap is not specified (or assigned a negative value) any restrictions exist on max distance between consecutive vias in the pattern.

Examples:

#define PCB level rule for staggered bbvias/microvias
rule PCB (staggered_via on (min_gap 0.1) (max_gap 0.8))

#redefine rule for staggered bbvias/microvias at ‘3_LAYER’
rule layer 3_LAYER (staggered_via on (min_gap 0.2) (max_gap 0.7))

#redefine rule for staggered bbvias/microvias of nets #from ‘NET_CLASS1’ class
rule class NET_CLASS1 (staggered_via on (min_gap 0.3) (max_gap 0.6))

#disable PCB level rule (similar rules at different hierarchy #levels are left enabled)
rule PCB (staggered_via off)

COST of Via Stagger Violation:


 

Cost descriptor values are interpreted by the PCB autorouter as follows:

- Forbidden, wrong staggered bbvia patterns aren't allowable for building (default)
- High, additional cost on wrong staggered bbvia patterns 100
- Medium, additional cost on wrong staggered bbvia patterns 25
- Low, additional cost on wrong staggered bbvia patterns 8
- Free, no additional cost on wrong staggered bbvia patterns


Note: At the “converge” stage (either after 5th routing iteration or during “filter” command execution) the autorouter resets this cost to the forbidden value automatically.
 

I look forward to your input on this capability.

Jerry "GenPart" Grzenia

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