At 06:48 AM 12/9/98 -0500, John D. Morin wrote:
>Does anyone know the significance of routing signals on an 8.333 mil
>grid? This is a customer requirement on a PCI card.

I would clarify with the customer exactly what they want.

Tango for DOS and its associated router had an 8.3 mil grid option. This
was *not* truly 8.3 mils. Rather, it was 0-8-17-25, since Tango had a one
mil database. This grid is *very* useful, since the positions 0-42-52-100
are on grid, and these are the precise positions of 8 mil traces with 8 mil
airgap between 60 mil IC pads. If one keeps vias on 100 mil grid where
possible, one can swing a trace clear across the board manually without
shorting to any pins....

Superroute had a 120 grids per inch option, which resulted in the same
roundoff positions.


[log in to unmask]
Abdulrahman Lomax
P.O. Box 690
El Verano, CA 95433

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