State-holding free NULL Convention Logic™

For several applications, such as those with low duty-cycles or event-driven activity, for which power consumption is a concern, asynchronous circuit design is very appealing. The main advantages are decreased power consumption and reduced electromagnetic interference (EMI). The NULL Convention Logic™ (NCL) paradigm provides an interesting way to design such circuits. This paper demonstrates that resources usage could be diminished by removing the state-holding capability of the 27 NCL gates. In this paper, we propose and discuss an effective means to obtain such reduced complexity circuits. The modified protocol proposed and validated in this paper leads to a substantial reduction, as high as 50%, of the resources required in a reported example. Moreover, by decreasing the number of gates, energy efficiency as well as operating frequency may be improved.