Dominance%20Fault%20Collapsing

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Dominance Fault Collapsing

• Ravi Chandra Paruchuri
• Spring 2004

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Definition

• If all tests of fault F2 detect another fault F1,
  then F2 is said to dominate F1.
• In summary,
• The n-input boolean gate requires n1 single
  stuck at faults to be modeled
• To collapse faults of a gate , all faults from
  the output can be eliminated retaining one type
  of fault (sa0 for AND and NAND sa1 for OR and
  NOR) on each input and the other type on any one
  of the inputs
• The output faults of the NOT gate and the wire
  can be removed as long as both faults on the
  input are retained
• No collapsing is possible for fan out

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Algorithm

1. Reads the .eqf file and picks up one fault from
   each line and stores it in a file say .txt file
2. Reads the number of inputs from .lev file
3. Retain all the faults from the primary inputs
4. Drop the fault if its on the output line
5. Pick the fault if its not on any primary input or
   on any output line
6. If the fault is 0 (.int file) and the gates (.lev
   file) are either AND or NAND, see whether the
   other inputs have a fan out or not . If the other
   input doesnt have fan out drop the fault else
   retain all the faults
7. Similarly, if the fault is 1 and the gates are
   either OR or NOR see whether the other inputs
   have a fan out or not. If the other input doesnt
   have fan out drop the fault else retain all the
   faults

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(No Transcript)
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Results

• The number of faults in the dominance collapsed
  set is 16 as compared to 22 of the equivalent
  collapsed set for circuit C17.
• The number of faults in the dominance collapsed
  set is 248 as compared to 301 of the equivalent
  collapsed set for the circuit 74181(ALU with NAND
  gates)
• All the results have been verified

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Demo !!!!
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Questions????