78 lines
3.9 KiB
HTML
78 lines
3.9 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<title>XSCHEM TUTORIAL</title>
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<link rel="stylesheet" type="text/css" href="xschem_man.css" />
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<style type="text/css">
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/* Local styling goes here */
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li{padding-top:2px;}
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p{line-height:1.4;padding: 20px 20px 0;text-align: justify;}
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</style>
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</head>
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<body>
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<!-- start of slide -->
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<div class="content">
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<!-- navigation buttons -->
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<a href="xschem_man.html" class="prev">PREV</a>
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<a href="xschem_man.html" class="home">UP</a>
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<!-- slide title -->
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<h1> WHAT IS XSCHEM </h1><br>
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<p>
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Electronic systems today tend to be generally very complex and a lot of work has to be done from
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circuit conception to the validation of the final product. One of the milestones of this process
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is the creation of the circuit schematic of the electronic system.
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</p><p>
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The circuit diagram has to be drawn using an interactive computer program called
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<em>schematic editor </em>, this is usually a very first step in the design cycle of the product.
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Once the schematic has been drawn on the computer, the circuit connectivity and device list
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<em>(netlist)</em> can be generated and sent to a circuit simulator (spice, hspice, eldo,
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just to mention some) for performing circuit simulation.
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</p><p>
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So, as you probably guessed, <b>XSCHEM</b> is a schematic capture program that allows to interactively
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enter an electronic circuit using a graphical and easy to use interface. When the schematic
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has been created a circuit netlist can be generated for simulation. Currently XSCHEM supports four
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netlist formats:
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</p>
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<ol>
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<li> SPICE netlist
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<li> VHDL netlist
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<li> VERILOG netlist
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<li> tEDAx netlist for Printed board editing software like <a href="http://repo.hu/projects/pcb-rnd">pcb-rnd</a>.
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</ol><p>
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XSCHEM was initially created for VLSI design, not for printed circuit board schematics (PCB), however the
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recently added tEDAx netlist format is used to export XSCHEM schematics to pcb-rnd or other tEDAx-aware PCB editors.
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The roadmap for XSCHEM development will focus more in the future to build a tight integration with
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<a href="http://repo.hu/projects/pcb-rnd">pcb-rnd</a> printed board editor, joining the
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<a href="http://repo.hu/projects/coraleda">CoralEDA</a> ecosystem philosophy.<br>
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XSCHEM initial design goal was to handle Integrated Circuit (IC) design and generate netlists for Very Large Scale digital,
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analog or mixed mode simulations. While the user interface looks very simple, the netlisting and rendering
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engine in XSCHEM are designed from the ground-up to handle in the most efficient way very large designs.
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Also the user interaction has no bells and whistles but is the result of doing actual work on big projects
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in the most efficient way. This is why for example most of the work is done with bind keys, instead of
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using context menus or elaborate graphical actions, simply these things will slow your work if most of
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your schematics have 5-8 levels of hierarchy and 1000K+ transistors.<br>
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Here under a picture of a VLSI SOC (System On Chip) imported in XSCHEM. As you can see the ability of XSCHEM is to handle
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really big designs. This has been the primary goal during the whole development of the program.
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The sample design showed has more than 10 levels of hierarchy and really big schematics. For each hierarchy level one
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component is expanded until the leaf of the tree is reached. :-)
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</p>
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<img src="big_design.png">
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<p>
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It is also worth to point out that XSCHEM has nothing to do with GSCHEM, the name similarity is just coincidence.
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<a href='http://wiki.geda-project.org/geda:gaf'>GSCHEM</a> is another powerful Schematic
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Capture program, primarily focused on board level (PCB) system design. See
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<a href='http://geda-project.org/'>gEDA</a> for more information.
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<!-- end of slide -->
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<div class="filler"></div>
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</div>
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</body>
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</html>
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