docs/wiki/geda-sn_readme.html

   1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
   2  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   3 <html>
   4 <head>
   5   <link rel="stylesheet" media="screen" type="text/css" href="./style.css" />
   6   <link rel="stylesheet" media="screen" type="text/css" href="./design.css" />
   7   <link rel="stylesheet" media="print" type="text/css" href="./print.css" />
   8
   9   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  10 </head>
  11 <body>
  12
  13 <h1 id="switcapnetlisterreadme">Switcap netlister README</h1>
  14 <div class="level1">
  15 <pre class="code">-----------------------------------------------------------------
  16 I.   What is this?
  17 -----------------------------------------------------------------
  18
  19 This archive contains a set of symbols and a netlister backend for the
  20 gEDA to drive SWITCAP simulations.  gEDA is the GNU EDA project and
  21 includes a schematic capture tool and a highly flexible netlister.
  22 The SWITCAP program is a switched capacitor circuit simulator.
  23
  24 -----------------------------------------------------------------
  25 II.  Overview
  26 -----------------------------------------------------------------
  27
  28 The basic steps involved with using gEDA as the frontend for SWITCAP
  29 simulations are:
  30
  31 - configure the gEDA symbol search path
  32 - set the gEDA netlister backend search path
  33 - create schematics of the circuit
  34 - create an analysis file
  35 - extract the netlist
  36 - run the SWITCAP simulation
  37
  38
  39 -----------------------------------------------------------------
  40 III.  Initial Setup
  41 -----------------------------------------------------------------
  42   1)  Set your symbol search path for gschem and gnetlist by adding
  43       the following line to the &#039;gschemrc&#039; and &#039;gnetlistrc&#039; files in
  44       your project directory.
  45
  46         (component-library &quot;/path/to/sym/switcap&quot;)
  47
  48       If those files do not exist, then create them.  You will need to
  49       replace /path/to/sym/switcap with the directory name where you
  50       have installed the .sym files.
  51
  52   2)  Set the search path for scheme files for gnetlist by adding the
  53       following line to your &#039;gnetlistrc&#039; file.
  54
  55         (scheme-directory &quot;/path/to/scheme&quot;)
  56
  57       You will need to replace /path/to/scheme with the path to where
  58       you have installed the gnet-switcap.scm file.
  59
  60   3)
  61
  62 -----------------------------------------------------------------
  63 IV.  Creating Schematics
  64 -----------------------------------------------------------------
  65
  66 --------------------
  67 A.  Required Symbols
  68 --------------------
  69
  70 This section assumes you are familiar with using gschem to create and
  71 edit schematics.  SWITCAP netlisting is only supported for the
  72 components contained in the SWITCAP symbol library as well as the
  73 ground symbol found in the &#039;power&#039; library which comes with gEDA.  All
  74 allowed SWITCAP elements except for subcircuits are supported.  You
  75 _must_ include the following elements on your schematic:
  76
  77 - one instance of the switcap-timing symbol.  This symbol will set the
  78   master clock period for your simulations.
  79
  80 - one or more instances of the switcap-clock symbol.  This symbol
  81   defines a clock with a particular phase and period.  The reference
  82   designator of the clock symbol is used by the switches to set what
  83   phase they switch on.
  84
  85 - one or more instances of the switcap-analysis symbol.  This symbol
  86   defines an analysis by specifying a file to include in the SWITCAP
  87   netlist.
  88
  89 --------------------
  90 B.  Optional Symbols
  91 --------------------
  92
  93 You can also optionally add the following SWITCAP special symbols to
  94 your schematic:
  95
  96 - zero or one instance of the switcap-title symbol.  This will add a
  97   TITLE: line to the SWITCAP netlist and will appear in the output
  98   file.
  99
 100 - zero or one instance of the switcap-options symbol.  By editing the
 101   OPTIONS attribute on this symbol you can set the various options
 102   which can be passed to SWITCAP.
 103
 104 --------------------
 105 C.  Net Names
 106 --------------------
 107
 108 When creating schematics to drive SWITCAP, you should name all nets
 109 that you wish to plot.  To avoid possible conflicts with unnamed nets,
 110 you should avoid using purely numerical names for nets because
 111 all unnamed nets will be assigned (somewhat randomly) numbers.
 112 SWITCAP limits the length of node names to 7 characters.
 113
 114 --------------------
 115 D.  Switches
 116 --------------------
 117
 118 When placing switches on your schematic, you will need to define
 119 which clock they are controlled with.  This is done by setting
 120 the clock attribute on the switch to the reference designator
 121 of the clock which should control it.
 122
 123 -----------------------------------------------------------------
 124 V.  Extracting the SWITCAP Netlist
 125 -----------------------------------------------------------------
 126
 127 To extract the SWITCAP netlist, run
 128
 129   gnetlist -g switcap -o test.scn file1.sch [file2.sch ...]
 130
 131 For the example file contained in this archive, you can run:
 132
 133   gnetlist -g switcap -o example.scn ckt.sch clocks.sch analysis.sch
 134
 135 The netlist will be left in example.scn.
 136
 137 -----------------------------------------------------------------
 138 VI.  Running SWITCAP
 139 -----------------------------------------------------------------
 140
 141 I typically use something like:
 142
 143   printf &quot;example.scn\nexample.out&quot; | sw
 144
 145 so I can use command history to rerun SWITCAP without having to
 146 manually type the file names each time.
 147
 148 Refer to the SWITCAP manual for more details.
 149
 150 </pre>
 151
 152 </div>
 153 </body>
 154 </html>