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<TITLE>Magic-7.3 Command Reference</TITLE>
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<H1> <IMG SRC=graphics/magic_title2.gif ALT="Magic VLSI Layout Tool Version 7.3">
<IMG SRC=graphics/magic_OGL_sm.gif ALIGN="top" ALT="*"> </H1>
<H2>extresist</H2>
<HR>
Patch the extraction <TT>.ext</TT> files with detailed route resistance
information.
<HR>
<H3>Usage:</H3>
<BLOCKQUOTE>
<B>extresist</B> <I>option</I> <BR><BR>
<BLOCKQUOTE>
where <I>option</I> may be one of the following:
<DL>
<DT> <B>tolerance</B> <I>value</I>
<DD> Set the ratio between resistor and transistor tolerance
for determining when to insert resistance into a network route.
<DT> <B>all</B>
<DD> Extract all the nets.
<DT> <B>simplify</B> [<B>on</B>|<B>off</B>]
<DD> Turn on/off simplification of resistor nets.
<DT> <B>extout</B> [<B>on</B>|<B>off</B>]
<DD> Turn on/off writing of the <TT>.res.ext</TT> file.
<DT> <B>lumped</B> [<B>on</B>|<B>off</B>]
<DD> Turn on/off writing of updated lumped resistances.
<DT> <B>silent</B> [<B>on</B>|<B>off</B>]
<DD> Turn off/on printing of net statistics.
<DT> <B>skip</B> <I>mask</I>
<DD> Don't extract types indicated in the comma-separated list <I>mask</I>
<DT> <B>box</B> <I>type</I>
<DD> Extract the signal under the cursor box on layer <I>type</I>
<DT> <B>cell</B> <I>cellname</I>
<DD> Extract the network for the cell named <I>cellname</I>
<DT> <B>geometry</B>
<DD> Extract network geometry and present as a collection of line
elements on the layout.
<DT> <B>fasthenry</B> [<I>freq</I>]
<DD> Extract subcircuit network geometry into a <B>fasthenry</B>-format
<TT>.fh</TT> file. If <I>freq</I> is specified, the file will
be customized for <B>fasthenry</B> analysis at the indicated
frequency (in Hz).
<DT> <B>help</B>
<DD> Print help information
</DL>
</BLOCKQUOTE>
</BLOCKQUOTE>
<H3>Summary:</H3>
<BLOCKQUOTE>
The normal flow through layout extraction into a simulation file
treats routes as nonphysical entities, that is, with infinitesimal
impedence through the wires. Extraction for digital simulation
using <B>irsim</B> generates "lumped resistances", a single
resistance per network node that, along with the node capacitance
to substrate, provides an <I>RC</I> time constant to approximately
model the delay from point to point in the network node. The
lumped resistance model is inappropriate for analog (i.e., SPICE)
simulation, and for digital simulation, is a poor approximation
for branching networks, where the delay between endpoints is
different for each pair of endpoints in the network node. <P>
The <B>extresist</B> command provides a method for generating
a more detailed model of resistance, in which long network
routes and branching routes are replaced with resistor devices
and device networks. <P>
Using <B>extresist</B> is a multi-step process. It is first
necessary to run both <B>extract</B> and <B>ext2sim</B> to get
the initial netlist (with lumped, not detailed, resistances).
After a <TT>.sim</TT> file has been generated, the
<B>extresist all</B> command may be run. The output is
a file <TT>.res.ext</TT> for each cell in the hierarchy.
Finally, with the option <B>extresist on</B> set,
<B>ext2sim</B> or <B>ext2spice</B> will generate the final,
detailed simulation file. <P>
More details on using <B>extresist</B> can be found in
<B>magic</B> Tutorial number 8.
</BLOCKQUOTE>
<H3>Implementation Notes:</H3>
<BLOCKQUOTE>
<B>extresist</B> is implemented as a built-in command in <B>magic</B>.
</BLOCKQUOTE>
<H3>See Also:</H3>
<BLOCKQUOTE>
<A HREF=extract.html><B>extract</B></A> <BR>
<A HREF=ext2sim.html><B>ext2sim</B></A> <BR>
</BLOCKQUOTE>
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<TABLE BORDER=0>
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<TD> <A HREF=commands.html>Return to command index</A>
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</TABLE>
<P><I>Last updated:</I> October 21, 2004 at 10:48am <P>
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