WriteCapaDoc.tioga
Christian LeCocq, December 8, 1986 5:03:34 pm PST
WRITECAPA
CEDAR 6.1 — FOR INTERNAL XEROX USE ONLY
WriteCapa : Capacitances values from Layout
Christian Le Cocq
© Copyright 1986 Xerox Corporation. All rights reserved.
Abstract: WriteCapa writes the capacitances of the layout wires as properties on the CoreWires
Created by: Christian Le Cocq
Maintained by: Christian Le Cocq <LeCocq.PA>
Keywords: Capacitance, Layout, Core Wire
XEROX  Xerox Corporation
   Palo Alto Research Center
   3333 Coyote Hill Road
   Palo Alto, California 94304

For Internal Xerox Use Only
WriteCapa is a package that explores the Core description of a layout and compute the stray capacitances of the wires from the ChipNDale associated data. Its purpose is mainly to produce an adequate input for Crystal, witch is now interfaced with Core. Two capacitances values are stored on each wire: the capacitance of this wire in its own hierachical level, and the capacitance from (and including) this wire to the lowest hierachical levels (= down to the transitor connections). The data structures implemented are compressed bitmaps, that combines simplicity and efficiency of full bitmaps to estimate areas, and efficiency of memory allocation, as only the meaningfull pixel borders are stocked. The package is interfaced with CoreIO to allow the client to save on disk the capacitances values.
The capacitances from the wires inside the transistor is now added to the line capacitances of the gate, ch1 and ch2 wires (Dec 86).