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Brief introduction to circuit simulation using logic-sim

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• How to simulate a digital circuit with logic-sim
  • Steps:

    Write a C-function named simnet() (simulation network) that defines the circuit that you want to simulate This C-function must be stored in a circuit file called: circuitFileName.cc Compile the circuit using the command: cs355sim circuitFileName When the compilation is successful, you can run the circuit simulation using this command: simex (Simulation execute)

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• Example
  • We first write the following circuit simulation:

    /* ===================================================================== * Always include this header file when writing digital simulation !!! * ===================================================================== */ #include "Sim.h" void simnet() { Sig(sw0,1); // Define sw0 as a signal Sig(sw1,1); // Define sw1 as a signal Sig(out,1); // Define out as a signal Switch ( "aa", sw0, 'a', Zero ); // Location = "aa", name = sw0, key = 'a' Switch ( "ca", sw1, 'b', One ); // Initial value: Zero or One And ( "bb", (sw0,sw1), out ); // And: inputs = (sw0,sw1), output = out // Note: ( .., .. ) group signals into 1 signal // Note: sw0 is equivalent to sw0[0] Probe ( "bc", out ); // Probe out }

    We save this circuit simulation in a file named and.cc

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  • Then we compile with this command:

    cs355sim and

    You will see this message:

    Circuit file(s): and.cc Done Use this command to run the circuit simulation: simex

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  • To run the circuit simulation, execute this command:

    simex

    and you will see this window:

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  • You can then interact with the circuit simulation by toggling the state of the switches in the circuit simulation

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  • Example Program: (Demo above code)                                                
    • Prog file: click here

    How to run the program:

    Right click on link and save in a scratch directory To compile:   cs355sim and To run:          ./simex