[Magic-dev] cifwidth oddity

[R. Timothy Edwards]

Dear Graham,

>    I'm using 7.5.95 and the cifwidth DRC check. I find that the values have to
> be twice the checked value. Eg.
> 
> style pharosc013 variants (55nm-vsclib)
> variant (55nm-vsclib)
> cifstyle pharosc013(55nm-vsclib)
> # POLY RULES
> cifwidth   CPG 24                 "3.1.01  POLY  Width < 0.12"
> cifspacing CPG CPG 20 touching_ok "3.2.01  POLY  Space < 0.20"
> 
> The spacing rule is OK but to check for a 0.2um width the value must be 24
> instead of 12.

Bertrand Irissou solved this for me recently, noting that the DRC-CIF
checks don't multiply by the CIF "expander" value (which is by default
2, thus the error of a factor of 2).  He submitted a correction for
the "drcCifSpacing()" routine, which is to add

     centidistance *= drcCifStyle->cs_expander;          // BSI

immediately after the "scalefactor =" line.  I assume that this is why
the "cifspacing" works correctly.  I also assume that the same change
needs to be made in each of the three other routines drcCifWidth(),
drcCifArea() (where it probably needs to be squared), and
drcCifMaxwidth().  Just add the same line in the equivalent place
for each routine.  I will update the distribution for Magic 7.4, but
as I mentioned  before, I have version 7.5 in a state of flux and will
not generate any new downloadable distributions until I have finished
coding changes to the (non-CIF) DRC code.

					Regards,
					Tim

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| Dr. R. Timothy Edwards (Tim)   | email: tim at opencircuitdesign.com    |
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