HomeworkLib
Question

5) Following is a NAND only 1-bit full adder circuit diagram. Using this 1-bit full adder a 128-bit combined addition / subtr

engineering   Computer-Science   
0 0
Add a comment Improve this question Transcribed image text
Next > < Previous
Sort answers by oldest

Homework Answers

Answer #1

15 NAND gates are required to implement 1-bit full adder

=> for operating 128-bits of input, we need 128 1-bit full adders

=> 128 * 15 NAND gates

= 1920 NAND gates (1 - to implement 128-bit full adder)

The above circuit will only perform addition operation. In order to support subtraction operation, we need to supply 2's complement of the input as an input to the full adder.

=> the second input has to be complemented for performing subtraction => need to use XOR gate

a mode input, M is used to distinguish between addition and subtraction operation.

if M = 0 => M XOR B => 0 XOR B => B

if M = 1 => M XOR B => 1 XOR B => B'

XOR gate again has to be implemented using 2-input NAND gates. It takes 4 NAND gates to implement one XOR gate

=> 128 * 4 NAND gates

=> 512 NAND gates   (2- to implement 2's complement of second input, B)

Overflow is detected by performing XOR operation on Carry out of 126th full adder, CO127 with Carry out of 127th full adder, CO128

=> required 4 NAND gates to implement one XOR gate

=> 4 NAND gates   (3 - to detect overflow)

Minimum number of NAND gates required to implement 128-bit combined addition/ subtraction circuit with overflow detection = 1920 + 512 + 4

= 2436 NAND gates

0 0
Add a comment
Know the answer?
Add Answer to:
5) Following is a NAND only 1-bit full adder circuit diagram. Using this 1-bit full adder...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions

  • Incorrect Question 19 0/0.25 pts How many NAND gates are needed to construct "overflow detection circuit"...

    Incorrect Question 19 0/0.25 pts How many NAND gates are needed to construct "overflow detection circuit" for a ripple carry adder/ subtractor combined circuit? Assume you are allowed to use only NAND gate in this circuit. 41

  • Build a 4 bit half adder only using nand gates. *logic diagram*

    Build a 4 bit half adder only using nand gates. *logic diagram*

  • Verify that your design can be represented by the circuit below. 120 Full-Adder circuit Many of...

    Verify that your design can be represented by the circuit below. 120 Full-Adder circuit Many of the logic gates you require may not exist in standard TTL/CMOS 74 series family of logic. For example in future designs you may require a 50 input OR gate. The 74 series does not have a 50 input OR gate. For your 1 bit adder you will have the following devices: 1 quad 2 IP NAND, 1 TRIPLE 3 IP NAND, 7400 7410 7404...

  • In quartus prime Implement a 4-bit adder/subtractor using structural VHDL. The circuit will have two 4-bit...

    In quartus prime Implement a 4-bit adder/subtractor using structural VHDL. The circuit will have two 4-bit data inputs (A and B), a control line (add /sub), a 4-bit sum output (S), a carry-out bit (Cout), and an overflow flag. You need two VHDL files (fulladd.vhd) and (hybrid.vhd) to implement the design. VHDL code, fulladd.vhd, will implement a single-bit full adder. The VHDL file, hybrid.vhd, will create four instances of the single-bit full adder. Four XOR gates will be needed to...

  • Given 4-bit ripple carry adders and logic gates (AND, OR, NOT, XOR, XNOR, NAND, NOR). Construct...

    Given 4-bit ripple carry adders and logic gates (AND, OR, NOT, XOR, XNOR, NAND, NOR). Construct a 12-bit adder/subtractor from the provided components. An input S will determine the type of operation. If S=0, it should add, otherwise subtract. DO THIS PLEASE. Show how you can simplify the circuit if you knew the circuit would always be adding 3. Start with the 4-bit ripple carry adder, set the value on input ‘B’ to the constant 3, and then reduce the...

  • Create a truth table to implement AND logic using only NAND gates. Draw the circuit diagram...

    Create a truth table to implement AND logic using only NAND gates. Draw the circuit diagram (schematic) for the implementation. Do the same for OR logic using only NOR gates.

  • Using single bit Full Adder (FA) blocks (as shown below) and required gates, construct a 6-bit...

    Using single bit Full Adder (FA) blocks (as shown below) and required gates, construct a 6-bit Adder/Subtractor for signed numbers. Use the signed two’s complement system for the signed numbers. Verify your design for the following addition and subtraction by specifying A as A5A4A3A2A1A0 and B as B5B6B3B2B1B0, determining the inputs to the FAs and their outputs and showing that the outputs correspond to the correct results: a) A-B with A = -13, B = +20 (5 points) b) A+B...

  • Tim Question 1 Atte 20 pts 2H 24 Design a 1-bit Full Adder using NOR gates...

    Tim Question 1 Atte 20 pts 2H 24 Design a 1-bit Full Adder using NOR gates only, you must include and show: Truth tables, detail logic gate circuit designs, and Boolean expressions Upload Choose a File 20 pts Question 2 Design a 4-bit Full Adder with inputs (Xo...X3, Yo...Y3) in which inputs X are connect to two 4-bit registers via four 2-to-1 Multiplexers and inputs Y are connected to two other 4-bit registers via four 2-to-1 Multiplexers. In this case...

  • 3. Digital circuits question. The figure below shows a 16-b carry-skip adder. It is composed of...

    3. Digital circuits question. The figure below shows a 16-b carry-skip adder. It is composed of 4 4-bit ripple carry adders and some extra logic to route the carry. Each 4bit ripple carry adder generates a group propagate signal. This is used to determine when the carry-in is going to be propagated all the way to the carry-out. When this is the case, addition is sped up by allowing the carry-in to skip the block and become the carry-in of...

  • First you must create a logic circuit using only basic gates such as AND, OR, NOR,...

    First you must create a logic circuit using only basic gates such as AND, OR, NOR, NAND, NOT, etc. to implement an ADDER capable of adding two 4 bit binary numbers. Second you must create a logic circuit using only basic gates such as AND, OR, NOR, NAND, NOT, etc. to implement a Subtractor that is capable of subtracting the second number from the first, by converting the second number into its 2's complement form and then adding the resulting...

ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT