8-Bit Binary-to-Gray Code Converter

1
8-Bit Binary-to-Gray Code Converter

• Mike Wong
• Scott Echols
• Advisor Dave Parent
• May 11, 2005

2
Agenda

• Abstract
• Introduction
• Why
• Simple Theory
• Back Ground information
• Summary of Results
• Project (Experimental) Details
• Results
• Cost Analysis
• Conclusions

3
Abstract

• 8-Bit Gray Code Converter
• Operates at 200 MHz
• Uses 5.65 mW of Power
• Occupies an area of 346x154 mm2

4
Introduction

• To convert a series of 8 binary numbers into Gray
  Code.
• Used in digital communication.
• When counting, only one bit is changed.
• Effect of error minimized.
• Uses the basic principles learned in EE166.

5
Introduction

• Truth Table

Binary Binary Binary Gray Code Gray Code Gray Code
3rd bit 2nd bit 1st bit Bit X Bit Y Bit Z
0 0 0 0 0 0 0
1 0 0 1 0 0 1
2 0 1 0 0 1 1
3 0 1 1 0 1 0
4 1 0 0 1 1 0
5 1 0 1 1 1 1
6 1 1 0 1 0 1
7 1 1 1 1 0 0
XOR Logic
Bit A Bit B XOR
0 0 0
0 1 1
1 0 1
1 1 0
6
Longest Path Calculations
Note All widths are in microns and capacitances
in fF
7
Schematic
8
Layout
9
Verification
10
Simulations
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Cost Analysis

• Time spent on each phase of the project
• verifying logic 1 week
• verifying timing 1 week
• layout 2 weeks
• post extracted timing 1 day

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Lessons Learned

• Use DRC often for the layout.
• Consult with Dr. Parent when needed.
• Start early and dont procrastinate.
• Smaller groups are easier to manage.

13
Summary

• Incorporated many of the principles taught in
  EE166.
• Designed a circuit that converts binary coded
  numbers to the Gray Code.
• Implemented logic design into layout form of CMOS
  technology.

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Acknowledgements

• Thanks to
• Cadence Design Systems for the VLSI lab
• Synopsys for Software donation.
• Professor Parent.