EDA & Numerical Analysis in GNU/Linux
-Ashwith Jerome Rego [email protected]
http://ashwith.wordpress.com
Before We Begin
Instructions
● Make sure you understand.● Stop me immediately if you don't.● Ask the volunteers (or me) for help during
the practical sessions.● There is no such thing as a silly question.
Why This Workshop?
● Robotics workshop done. What next?
● Equipment isn't cheap.
● Give you legal tools and encourage research.
● Make you start early (2nd year or earlier is ideal).
● Industry tools are similar.
● Jump start into EDA. Then self explore.
● Ethical reasons.
● Encourage FOSS.
● Open source – You can see how they work and even tinker around!
Why Fedora (Electronic Lab)?● Bleeding edge GNU/Linux distribution.● FEL is maintained by people in the
electronics industry.● Aims to be a complete package which
meets industry standards.
A Small Note About The “Tinker” Part● Do you like electronics stream subjects as
well as coding?● Look at the code in these projects.● If you're up for it, join them.● Example: DSP/DIP is pretty popular in
college. Consider gimp & audacity.● gEDA has been a GSOC project in the
past.
What Will We Learn Today?
● Unix Basics.● gEDA (parts of it)
– Schematic Capture
– Symbol Creation
– SPICE simulations
● Scilab– Language Basics
– Some Mathematical Applications
– Engineering Applications
– Xcos demos
What Will We Be Introduced To?● Python Programming● Sagemath● Maxima● Octave
Unix – Basic Tutorial
gEDA Workshop
gEDA
● EDA tools under the GPL license.● Circuit Design.● Schematic Capture.● Simulation● Prototyping.● Production.● www.geda-project.org
Procedure
NetlistNetlistGenerationGeneration
SimulationSimulation ResultsResults
PCB DesignPCB Design(Not Today)(Not Today)
SchematicSchematicCaptureCapture
Symbol Symbol CreationCreation
Drawing Your Circuit: Schematic Capture● Settings: ~/.gEDA/gschemrc &
~/.gEDA/gafrc● Program: gschem● Example 1:
Schematic to SPICE Netlist
● Program: gnetlist.● What is a SPICE netlist?● Learn to write the netlist yourself.
Final Step: Simulation & Plotting● Simulation Program: ngspice● Types of analysis (ones you'll be doing today).
– DC
– TRAN
– AC
● You best friend:
evince `rpm -ql ngspice |grep pdf`
● Plotting Program: gaw
Device Models, TRAN & Example 2
● Source types: Check your “best friend”. We need a sinusoid.
● We need a way to specify the behavior of 1N4004 (Check your best friend again). Go online.
AC Analysis & Example 3
● AC sources
Your Turn – Exercise 1: Diode Characteristics
● What type of simulation will you use?● Measuring current?
Exercise 2: Colpitts Oscillator
● Mutual Inductance?!
Symbols & Subcircuits:Hierarchical Design
● Opamps are not SPICE primitives. What do we do?
The 741 Symbol
Add Symbol To Library
● ~/.gEDA/gafrc
(component-library "/home/fel/fel-workshop/gEDA/symbols")
Back To the HPF: Exercise 3● You know what to do – run an AC analysis
from 1Hz to 200KHz
What Next?
● Use this to play with circuits.● Don't blindly believe what the book says –
Check it!● Explore and discover more details on your
own.● Check out KiCad and pcb.
Introduction to Icarus Verilog● Easy to self learn: http://iverilog.wikia.com/ ● Demo
Other Tools
● Arduino● Fritzing● MSP430 GCC● Alliance VLSI CAD● Electric VLSI● Magic VLSI Layout
Scilab
What Use It?
● Free of charge● Interested in starting a company? Don't
need to worry about licensing.● Free & Open Source – Change it the way
you like.● Ariane space program uses it – out
satellites are in space thanks to their rockets.
● http://www.scilab.org/scilab/gallery/applications
But We Got Matlab + Torrents!● Don't try you luck with that in research –
you need to do things legally.● Can't do this if you want to start a company
either.● It's not right to steal.● Encourage the use of FOSS software – it
will drive improvement.
Language Basics
● Variables & Assignments● Basic Operations● Matrices● Branching & Looping● Functions● Plotting● Strings & Printing● Useful functions
Mathematics
● Linear Algebra● Differential Equations● A lot more possible (complex algebra,
statistics, calculus, etc)
On To Engineering
● Signals & Systems● Control Systems● Filter Design Examples● Elementary Image Processing (Scilab can
do a lot more though)
Xcos
References
● http://www.geda-project.org/
● http://iverilog.wikia.com/
● ngspice manual
● Presentations on Scilab by IITB (available at www.scilab.in)
● Master Scicos by Finn Haugen (home.hit.no/~finnh/scilab_scicos/scicos/)
● Digital Signal Processing – A Computer Based Approach – S. K. Mitra
● Digital Signal Processing using MATLAB – Vinay K. Ingle & John G. Proakis
● Signals & Systems – Simon Haykin & Barry Van Veen
● Signals & Systems – A. V. Oppenheim, A. S. Willsky & S. H. Nawab
● Modern Control Engineering – K. Ogata
Any Questions?
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