diff --git a/VERSION b/VERSION index ae074d55..23bbf6e6 100644 --- a/VERSION +++ b/VERSION @@ -1 +1 @@ -8.3.653 +8.3.654 diff --git a/doc/html/extresist.html b/doc/html/extresist.html index 9b9d7b13..b69e256b 100644 --- a/doc/html/extresist.html +++ b/doc/html/extresist.html @@ -30,11 +30,31 @@ information.
where option may be one of the following:-
@@ -79,9 +101,9 @@ information.- tolerance value -
- Set the ratio between resistor and transistor tolerance - for determining when to insert resistance into a network route.
- all
- Extract all the nets. +
- threshold [value] +
- With no value given, returns the current lumped resistance + threshold used to determine if a network will or will not be + analyzed for resistance extraction, in milliohms. The default + threshold value is 10000 milliohms (10 ohms). If + value is given, then set the lumped resistance threshold + to value milliohms. +
- mindelay [value] +
- With no value given, returns the current delay time threshold + used to determine if a network will or will not be analyzed for + resistance extraction, in picoseconds. The default + mindelay value is zero, indicating that delay time is + not used for determining extraction. If value is given, + then set the delay threshold to value picoseconds. +
- minres [value] +
- With no value given, returns the current absolute resistance + threshold used to prune small resistances from a network when + simplifying, in milliohms. The default minres value + is 1000 milliohms (1 ohm). If value is given, then set + the absolute resistance threshold to value milliohms. + Note that resistances smaller than value may still + appear in the output netlist if the algorithm is unable to + simplify the network around the resistor.
- simplify [on|off]
- Turn on/off simplification of resistor nets.
- extout [on|off] @@ -69,6 +89,8 @@ information. .fh file. If freq is specified, the file will be customized for fasthenry analysis at the indicated frequency (in Hz). +
- tolerance value +
- Deprecated! This option is no longer used by extresist.
- help
- Print help information
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 irsim generates "lumped resistances", a single - resistance per network node that, along with the node capacitance + impedence through the wires. Standard extraction generates "lumped + resistance" values, a single resistance per network node that, along + with the node capacitance to substrate, provides an RC 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) @@ -96,10 +118,9 @@ information. Using extresist as a standalone command is a multi-step process. It is first necessary to run extract to get - the initial netlist. - After a .ext file has been generated, the - extresist command may be run. The output is - a file .res.ext for each cell in the hierarchy. + the initial netlist. After a .ext file has been generated, + the extresist command may be run. The output is a file + .res.ext for each cell in the hierarchy. Finally, with the option extresist on set, ext2spice will generate the final, detailed simulation file.@@ -110,7 +131,42 @@ information. magic version 8.3.597 an option extract do resistance that runs the resistance extraction in sequence with the regular extraction, producing both the .ext and .res.ext - files. + files. When extract do resistance is used, there is no need + to run extresist as a separate command. However, + extresist may be run prior to extract to set the + options that affect resistance network extraction, such as + extresist threshold, extresist minres, etc.
+ + As of magic version 8.3.653, the extresist tolerance option + is deprecated and has no effect on network resistance extraction. + Instead, extraction is controlled by three main options:
+ + extresist threshold (value in milliohms) sets a cutoff for + considering a network for detailed resistance extraction based on + the lumped resistance estimate (see above). For point-to-point + wires, the lumped resistance is approximately equal to the actual + wire resistance. For branching networks, it will generally be an + over-estimate. The default threshold value is set to + 10 ohms.
+ + extresist minres (value in milliohms) sets a cutoff for + individual resistors in the detailed resistor network. Resistors + below this threshold will get pruned out of the network if the + simplification algorithm is able to remove them. The default + minres value is set to 1 ohm.
+ + extresist mindelay (value in picoseconds) sets a cutoff for + considering a network for detailed resistance extraction based on + the end-to-end delay calculated from the lumped resistance + estimate. Once the network has been extracted, the mindelay + value is again evaluated against a revised calculation of the + delay to determine if the extracted detailed network should be + output. The default mindelay value is set to 0, indicating + that only the lumped resistance threshold should be used for + determining when to extract a detailed resistance network. + mindelay may be used in place of threshold, or both + may be used together, in which case a network is only extracted + if both threshold and mindelay are exceeded.
More details on using extresist can be found in magic Tutorial number 8. @@ -134,6 +190,6 @@ information.
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Last updated: May 29, 2026 at 11:33am