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geda:sn_readme [2012/02/20 15:14]
geda:sn_readme [2012/02/20 15:14] (current)
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 +====== Switcap netlister README ======
 +<​code>​-----------------------------------------------------------------
 +I.   What is this?
 +-----------------------------------------------------------------
  
 +This archive contains a set of symbols and a netlister backend for the
 +gEDA to drive SWITCAP simulations. ​ gEDA is the GNU EDA project and
 +includes a schematic capture tool and a highly flexible netlister.
 +The SWITCAP program is a switched capacitor circuit simulator.
 +
 +-----------------------------------------------------------------
 +II.  Overview
 +-----------------------------------------------------------------
 +
 +The basic steps involved with using gEDA as the frontend for SWITCAP
 +simulations are:
 +
 +- configure the gEDA symbol search path
 +- set the gEDA netlister backend search path
 +- create schematics of the circuit
 +- create an analysis file
 +- extract the netlist
 +- run the SWITCAP simulation
 +
 +
 +-----------------------------------------------------------------
 +III.  Initial Setup
 +-----------------------------------------------------------------
 +  1)  Set your symbol search path for gschem and gnetlist by adding
 +      the following line to the '​gschemrc'​ and '​gnetlistrc'​ files in
 +      your project directory.  ​
 +
 +        (component-library "/​path/​to/​sym/​switcap"​)
 +
 +      If those files do not exist, then create them.  You will need to
 +      replace /​path/​to/​sym/​switcap with the directory name where you
 +      have installed the .sym files.
 +
 +  2)  Set the search path for scheme files for gnetlist by adding the
 +      following line to your '​gnetlistrc'​ file.
 +
 +        (scheme-directory "/​path/​to/​scheme"​)
 +
 +      You will need to replace /​path/​to/​scheme with the path to where
 +      you have installed the gnet-switcap.scm file.
 +
 +  3)  ​
 +
 +-----------------------------------------------------------------
 +IV.  Creating Schematics
 +-----------------------------------------------------------------
 +
 +--------------------
 +A.  Required Symbols
 +--------------------
 +
 +This section assumes you are familiar with using gschem to create and
 +edit schematics. ​ SWITCAP netlisting is only supported for the
 +components contained in the SWITCAP symbol library as well as the
 +ground symbol found in the '​power'​ library which comes with gEDA.  All
 +allowed SWITCAP elements except for subcircuits are supported. ​ You
 +_must_ include the following elements on your schematic:
 +
 +- one instance of the switcap-timing symbol. ​ This symbol will set the
 +  master clock period for your simulations.
 +
 +- one or more instances of the switcap-clock symbol. ​ This symbol
 +  defines a clock with a particular phase and period. ​ The reference
 +  designator of the clock symbol is used by the switches to set what
 +  phase they switch on.
 +
 +- one or more instances of the switcap-analysis symbol. ​ This symbol
 +  defines an analysis by specifying a file to include in the SWITCAP
 +  netlist.
 +
 +--------------------
 +B.  Optional Symbols
 +--------------------
 +
 +You can also optionally add the following SWITCAP special symbols to
 +your schematic:
 +
 +- zero or one instance of the switcap-title symbol. ​ This will add a
 +  TITLE: line to the SWITCAP netlist and will appear in the output
 +  file.
 +
 +- zero or one instance of the switcap-options symbol. ​ By editing the
 +  OPTIONS attribute on this symbol you can set the various options
 +  which can be passed to SWITCAP.
 +
 +--------------------
 +C.  Net Names
 +--------------------
 +
 +When creating schematics to drive SWITCAP, you should name all nets
 +that you wish to plot.  To avoid possible conflicts with unnamed nets,
 +you should avoid using purely numerical names for nets because
 +all unnamed nets will be assigned (somewhat randomly) numbers.
 +SWITCAP limits the length of node names to 7 characters.
 +
 +--------------------
 +D.  Switches
 +--------------------
 +
 +When placing switches on your schematic, you will need to define
 +which clock they are controlled with.  This is done by setting
 +the clock attribute on the switch to the reference designator ​
 +of the clock which should control it.
 +
 +-----------------------------------------------------------------
 +V.  Extracting the SWITCAP Netlist
 +-----------------------------------------------------------------
 +
 +To extract the SWITCAP netlist, run
 +
 +  gnetlist -g switcap -o test.scn file1.sch [file2.sch ...]
 +
 +For the example file contained in this archive, you can run:
 +
 +  gnetlist -g switcap -o example.scn ckt.sch clocks.sch analysis.sch
 +
 +The netlist will be left in example.scn.
 +
 +-----------------------------------------------------------------
 +VI.  Running SWITCAP
 +-----------------------------------------------------------------
 +
 +I typically use something like:
 +
 +  printf "​example.scn\nexample.out"​ | sw
 +
 +so I can use command history to rerun SWITCAP without having to
 +manually type the file names each time.
 +
 +Refer to the SWITCAP manual for more details.
 +
 +
 +</​code>​
geda/sn_readme.txt ยท Last modified: 2012/02/20 15:14 (external edit)