NCL Circuit Behavior

Null Convention Logic

  • A complete and coherent logic sufficiently expressive to construct an entire system solely in terms of Null Convention Logic
  • Two values, data and null (not-data), and the NCL dual threshold logic with hysteresis behavior that appreciates monotonic transitions between the two.
  • The null value establishes a background of not-data or emptiness which data values spontaneously flow through.
  • NCL is a multi-value/multi-rail logic. Variable values are represented with one rail per value.

These movies illustrate how the threshold behavior, the hysteresis behavior and the multi-rail behavior of NCL logic functions produce logically determined glitch free flow through  combinational circuits.

Half adder: Illustrates flow and completeness behavior of successive data and null wavefronts.

The above circuit: Illustrates flow and completeness behavior with simultaneous inputs.

The above circuit: Illustrates flow and completeness behavior with non-simultaneous inputs.

The done rail indicating completeness of the function reaches back to the input source, is inverted and closing an oscillation about the function allows the succeeding monotonic transition of the input. This oscillation behavior regulates the flow through the function. This completeness/enable structure links oscillations into structures of self regulating computation flow. Data completeness allows null flow. Null completeness allows data flow. Below is a first order illustration of the linked oscillation flow.

Below is a combinational structure of linked oscillations entirely in terms of NCL.

2 bit multiplyB-46

The movie below illustrate the behavior of a system composed as a structure of linked oscillations.