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      Filename:  README

   Description:  Automatic Test Pattern Generator for combinational
                 circuits.

       Version:  1.0
       Created:  12/02/2011

        Author:  Aditya Shevade <aditya.shevade@gmail.com>,
                 Amey Marathe <marathe.amey@gmail.com>,
                 Samik Biswas <samiksb@gmail.com>,
                 Viraj Bhogle <viraj.bhogle@gmail.com>

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This code generates test patterns to detect faults in a combinational circuit.
The program takes in 2 parameters. The circuit file and the fault list.
This code only works on single stuck at faults (one fault at a time).

It then performs fault collapsing on the circuit, considering all faults possible.
After collapse, it generates a list of vectors to test for faults on all the faults from
this collapsed list.

The second parameter is a list of line number in the circuit and the corresponding fault 
to be checked. The program returns one vector per fault in this file which, when applied
can detect the fault in the circuit.

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Circuit File Format
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  The circuit format (called "self" format) is based on outputs of
  a ISCAS 85 format translator written by Dr. Sandeep Gupta.
  The format uses only integers to represent circuit information.
  The format is as follows:

1        2        3        4           5           6 ...
------   -------  -------  ---------   --------    --------
0 GATE   outline  0 IPT    #_of_fout   #_of_fin    inlines
                  1 BRCH
                  2 XOR
                  3 OR
                  4 NOR
                  5 NOT
                  6 NAND
                  7 AND
                  8 XNOR (Currently not implemented)

1 PI     outline  0        #_of_fout   0

2 FB     outline  1 BRCH   inline

3 PO     outline  2 - 7    0           #_of_fin    inlines

----------------------------------------------------------------------------------------

For example, if the first column is 0 then it's a gate. Second column is the output of
the gate. Outline, also called line number, is unique. Third column is the type of the
gate. Column 4 is the number of fan-out (how many outputs this gate drives. The fifth
column is the number of inputs to the gate. Column 6-N are the line numbers of the
inputs to the gate.

Similarly for PI (Primary input of the circuit), PO (Primary output of the circuit)
and FB (Branches).

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Restrictions
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The code is currently only capable of working with 3 input gates.
XNOR is not implemented yet.

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Running the Code
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Once in the source directory, run make to compile the program.
Once compiled, run the program as
    
    ./atpg x.ckt y.flt

Where x.ckt is the circuit file and y.flt is the fault list file.

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