1 8-Bit Barrel Shifter Cyrus Thomas Ekemini Essien Kuang-Wai (Kenneth) Tseng Advisor: Dr. David Parent December 8, 2004

2 Agenda Abstract Introduction –Why –Simple Theory –Back Ground information (Lit Review) Summary of Results Project (Experimental) Details Results Cost Analysis Conclusions

3 Abstract Designed and Verified an 8-bit Barrel Shifter that operates at 200 MHz, uses mW of Power, occupies an area of 340 x 300  m 2 and has a power density of 15.1 W/cm 2. The shifter works by shifting the bits left. Inputs: Data bits D0-D7 & encoded Select lines S2, S1, S0. Outputs: Shifted Data bits Q0 – Q7. Implementation Technology : 0.6 micron process. Latency = 5n s. External load driving capability = 33f F. Number of Metal layers used = 3.

4 Introduction Because there were 5 stages (combining each flip flop stage as one stage), the propagation delay time was divided amongst all 5 stages with each stage having a different driving capacitance. Since each output of multiplexer in stage 2 and 3 was connected to 2 other multiplexers, the fan out was 2. Since the connection from the multiplexers have long wires through out the circuit, parasitic capacitances were considered for sizing.

5 8 Bit Barrel Shifter Logic Diagram Stage 1Stage 2 Stage 3Stage 4Stage 5

6 Project Summary We designed a 8 bit Barrel Shifter that shifts data from an input to an output depending on the combination of three select lines. Our design of the Barrel shifter allows for an increase in the number of input bits without having to modify the existing design. Our design met the specifications for the project.

7 Longest Path Calculations Note: All widths are in microns and capacitances in fF

8 Schematic

9 Layout

10 Verification

11 Simulations

12 Cost Analysis We had to invest our time and resources to complete this project. By our estimation, considering that we also had to study for other classes, we spent –12 hours worth of time in a week and a half looking for and deciding on a project with Dr. Parent’s consent. –8 hours worth of time in a week verifying our logic and making our schematic. –6 hours worth of time in a day verifying our timing. –36 hours worth of time in two and half weeks making the layout of our project. –8 hours of time in a week in determining our post extraction time.

13 Lessons Learned Doing the project helps in better understanding the course material. Start the project on time as the earlier you start, the better. Consult with the course instructor (Dr. Parent in this case) and your peers whenever you get stuck on the project as no one can know it all. And most importantly view the project as an opportunity to have fun while learning. It will make it a worthwhile experience.

14 Summary Our project was a worthwhile endeavor as not many people know what a barrel shifter is and what it is used for. As such, doing it and presenting it to the class has helped to enlighten our classmates. Most importantly we got our circuit design to work and meet specification as we have ably shown in our presentation. We believe that our circuit can become a stepping stone to improving computer organization and memory.

15 Acknowledgements Thanks to each member of the group for putting up with one another. Thanks to Cadence Design Systems for the VLSI lab Thanks to Synopsys for Software donation Thanks to Professor Parent for his assistance and advising with the project. Thanks to you all for listening.