8-bit ALU

(AND, OR, ADD, SUB)

Basic Building Blocks

• To initiate the project, we needed to create the basic building blocks: AND, NAND, OR, and NOR gates.

• Since a NOR gate and NAND gate input with Anot and Bnot are a AND gate and a OR gate, respectively, we need only design a NOR and NAND.

NOR Layout

NOR Transient

NAND Layout

NAND Transient

Data Holding and Selection

• To store data, we used D flip-flops at data input and data output.– Usage of the D flip-flops also gave our team

access to the Anot and Bnot needed for the AND and OR gates.

• For data selection at the output, we used 4-1 MUX’s for each bit.

D Flip-Flop Schematic/Transient

D Flip-Flop Layout

MUX Schematic/Transient

Mux Layout

XOR (used in Adder/Subtractor)

XOR Layout XOR Transient

1-bit Full Adder

Schematic

Transient

Layout

1-bit Full Subtractor

Schematic

Transient

Layout

1-bit ALU

1-bit ALU

1-bit ALU

8-bit AND

8-bit OR

8-bit ALU Layout

Conclusion

• This project was successful due to teamwork and dedication.

• My team and I were able to design, test, and build an 8-bit ALU with emphasis on minimum chip size and maximum speed.