Circuit testibility related

Discussion in 'Homework Help' started by popeyes, Mar 24, 2013.

  1. popeyes

    Thread Starter New Member

    Feb 25, 2013
    given a function f() to check the tautology of a Boolean expression.
    return true if the Boolean exp can be reduced to 1.

    How to use this function f() to determine a combinational circuit's testability.

    I am thinking to use the reduce to 1 property, so for the fault excitation, if it's stuck at 1, if call f() at this node with this node's boolean exp, if it returns true, then it's untestable.for stuck at 0,invert the boolean exp before this node, and call f(), if it returns 1, then it's untestable.

    For fault propagate, very similar idea, call f at the next gate's output, if it can return true for stuck at 1, then this is untestable.

    But I am just so not sure about this logic. First, I cant define the relation between the f() return's 1 and circuit's testability, seems to me it's more like redundant. Second, I am not sure if other paths also need to be considered.

    Anyone can help?