Theses and Dissertations - UTB/UTPA

Date of Award


Document Type


Degree Name

Master of Science (MS)


Electrical Engineering

First Advisor

Dr. Weidong Kuang

Second Advisor

Dr. Hasina Huq

Third Advisor

Dr. Sanjeev Kumar


Asynchronous methodologies, such as Null Convention Logic (NCL), have tremendous potential in implementing digital logic. It is essential to design complex asynchronous circuits using commercial Electronic Design Automation (EDA) tools. The main focus of this thesis is to design NCL circuits using VHDL and implementing them on FPGAs. The major contributions of this thesis include: 1) Developing a methodology of designing NCL circuits with VHDL and applying it successfully to all practical designs in this thesis. 2) As an example, the NCL circuit for DES (Data Encryption Standard) algorithm has been designed and simulated using VHDL and the implementation issues on various FPGAs (Xilinx and Altera) have been investigated. Modification of the design has been done to minimize the amount of logic used. 3) An effective soft error tolerant scheme for asynchronous circuits on FPGAs is proposed, and successfully verified through software simulation and hardware implementation by introducing it into a DES round. This thesis provides a starting point for further investigation of NCL circuits, in terms of VHDL modeling, FPGA implementations, and soft error tolerance.


Copyright 2009 Deepya Reddy Nalubolu. All Rights Reserved.

Granting Institution

University of Texas-Pan American