Seminar assignments - Lab report 4 PDF

Preview

Summary

Download Seminar assignments - Lab report 4 PDF

Description

Code Conversion Dmytro Haydamakha CSE 2300W (Digital Logic Design) SEC001L TA: Sowmya Kotha Date: 02/25/2016

Objectives: The main objective of this lab assignment is to build and design a conversion circuit that will convert POSTNET code to the BCD code. Therefore we will use POSTNET code as an input and BCD code as an output. POSTNET is a barcode that includes high bars and half bars in it. High bars represent 1’s digit and half bars represent 0’s digit. It has 5 bits in binary numerical system. BCD is 4-digit binary code that has goes from 0 to 10 in decimal numerical system. This conversion circuit can be useful when delivering mail by zip code.

Introduction: For this lab it is important to understand how to use Karnaugh Maps, which can be used for derivation of our minterm equations. Also we should be familiar with don’t cares which can be used to minimize our equations. The don’t cares usually appear when the input values for the minterm do not occur and they have the designation of “X” in the truth tables or Karnaugh Maps. After the derivation of equations, we should be able to build and design the circuit that will convert correctly from POSTNET code to BCD code. POSTNET 5 bits will be labeled V,W,X,Y,Z. Then we should be able to recreate our circuit design on protoboard by using 7405, 7404, 7432 chips, and wires in order to make connections. Procedure: Step 1: -Create the table with decimal, POSTNET code (V,W,X,Y,Z) and BCD output (D,C,B,A) that goes from 0 to 9 in decimal and compare the conversions.

-In order to build the conversion circuit, we need to create a 5 variable Karnaugh Map for each output D,C,B,A. Step 2 : - Fill in all of the values from the table we have created before. -Each output should have two Karnaugh Maps for V= 0 (V’) and for V= 1 (V). -First, mark all of the don’t cares that that appear in each Karnaugh Map -Then fill the rest of the map cells with 0’s and 1’s. Step 3 : -Group the 1’s together in order to derive Boolean functions. -Use don’t cares when necessary, because they might help to minimize the equation, therefore minimize the use of gates. -Finally, write down Boolean functions for D, C, B and A. Step 4 : -Open the LogicWorks application in order to build the design by using derived Boolean functions. -Use switches for your input values and Hex display for your output values. -Use AND, OR and NOT gates to fulfill the functions onto the circuit. Step 5 : -Make sure that your circuit works for all of the POSTNET code values from 0 to 9. -Debug the circuit if necessary. Step 6 :

-Recreate the circuit on the protoboard by using wires, switch, resistors, LEDs and 7405, 7404, 7432 chips.

Results: -Table of values from 0 to 9 in decimal:

Decimal

Postnet (VWXYZ)

BCD Output (DCBA)

0

11000

0000

1

00011

0001

2

00101

0010

3

00110

0011

4

01001

0100

5

01010

0101

6

01100

0110

7

10001

0111

8

10010

1000

9

10100

1001

-Below I created 5 variable Karnaugh Maps for each output (DCBA): D)

V’

WX/ YZ

00

01

11

10

00

X

X

0

X

01

X

0

X

0

11

0

X

X

X

10

X

0

X

0

V WX/ YZ

00

01

11

10

00

X

0

X

1

01

1

X

X

X

11

X

X

X

X

10

0

X

X

X

C)

V’

WX/ YZ

00

01

11

10

00

X

X

0

X

01

X

0

X

0

11

1

X

X

X

10

X

1

X

1

V WX/ YZ

00 01

11

10

00

X

1

X

0

01

0

X

X

X

11

X

X

X

X

10

0

X

X

X

B)

V’

WX/ YZ

00

01

11

10

00

X

X

0

X

01

X

1

X

1

11

1

X

X

X

10

X

0

X

0

V WX/ YZ

00

01

11

10

00

X

1

X

0

01

0

X

X

X

11

X

X

X

X

10

0

X

X

X

A)

V’

WX/ YZ

00

01

11

10

00

X

X

1

X

01

X

0

X

1

11

0

X

X

X

10

X

0

X

1

V WX/ YZ

00

01

11

10

00

X

1

X

0

01

1

X

X

X

11

X

X

X

X

10

0

X

X

X

-Boolean functions are written below: D = VY + VX; C = V’W + VZ; B = V’X + VZ; A = V’Y + VZ + VX. -Below there is my final design of the circuit that implements the equations above:

-The picture of the protoboard circuit is attached to submission separately from this document. Discussion: During this lab assignment I have completed all of my 5 variable Karnaugh Maps and designed the circuit in LogicWorks without any trouble or errors. But when I finished building the circuit on the protoboard it wasn’t implementing the correct outputs, therefore I had to fix it. My main error for breadboard design is disorganized placed wires. From my mistake I understood how important it is to build the circuit with easy following design. It is just like with circuits in LogicWorks. Conclusion: Ultimately, I was able to build the circuit that converts POSTNET code to the BCD code. LogicWorks is very useful tool when it comes to designing circuits before actually building them on the protoboard. From this lab I learned how important it is to use shorter wires for the protoboard circuit, because due to my mistake I couldn’t find the error that would fix my conversion circuit and displays the correct outputs. I had to rebuild it.

POSTNET symbology code for my home area: 0

6

9

0

7

-

1

8

1

4

||||| ||||| ||||| ||||| ||||| ||||| ||||| ||||| ||||| Questions: 1. How many non-valid input codes are there? 1) I am not sure about this question, but I would be happy to know the right answer.

I think that POSTNET only supports 5 and 9 digit zip codes, therefore other would be non-valid. 2.Would your design be simpler if there was no zero input? Does your design conflict with your answer? 2) Yes my design could have been simpler if there was no zero inputs because we can minimize even more by using Karnaugh Maps. No my design doesn’t conflict with my answer. References: This reference was given to us by KB http://www.barcodeisland.com/postnet.phtml...