Digital Electronic Circuits
ASSIGNMENT
You will undertake a number of investigative and practical activities designed to develop your understanding of digital electronic circuits.
ASSIGNMENT OBJECTIVES
In this assignment, for LO3, you will need to show that you candesign, build and test digital electronic circuits.
LO3.1Compare different digital electronic device families
LO3.2Design and construct combinational and sequential digital electronic circuits using logic devices
LO3.3 Test digital electronic circuits
TASK INTRODUCTION
You have completed your engineering apprenticeship and have a position in the design department of your company. You have been asked by your line manager to analyse logic families and to produce combinational and sequential logic circuits.
TASK 1:
a) Using Manufacturer's datasheets complete a table using Nominal values for the following logic families: LS TTL, ALS TTL, CMOS, HCMOS. (Include excerpts from datasheet in appendix)
b) Briefly explain the different types of scales of integration: SSI, MSI, LSI, VLSI. (one sentence each)
c) Briefly explain the different types of programmable devices: PROM, PAL, PLA. (one-two sentances)
TASK 2:
You are to design a 3-bit counter with outputs Q0, Q1, Q2, where Q0 is the least significant bit.
The sequence 0, 2, 3, 5, 7, 6, 4, 0, 2 ... is generated:
010 (2)
011 (3)
101 (5)
111 (7)
110 (6)
100 (4)
000 (0)
Then repeat
Part 1
Design the circuit. (Use any type of flip-flops eg JK T or D, and any gates)
Include truth tables and Karnaugh maps in your answer
Opportunity for merit
Design the circuit using only another type of flip-flop and NAND gates logic.M2
Opportunity for merit
Re-design the circuit with an UP/DOWN counter input, so that the sequence can be reversed.
The counter has a single input D, when D is low the counter counts up the sequence, when D is high the counter counts down the sequence.
Use the Moore model (This requires outputs to be decoded)
Your answer should include truth tables, Karnaugh maps.M1
Part 2
Using circuit simulation software, draw a circuit diagram from Task 2, Part 1 and simulate its operation.
Demonstrate the circuit operation to your tutor.
Opportunity for Distinction
Re-design the circuit with an UP/DOWN counter input, so that the sequence can be reversed.
The counter has a single input D, when D is low the counter counts up the sequence, when D is high the counter counts down the sequence.
Use the Mealy model.
Your answer should include truth tables, Karnaugh maps and be made using only JK type flips flops. Demonstrate to your tutor that the circuit works using simulation software.D3
TASK 3:
Part 1
Design a circuit using only NAND gates, whose output goes HIGH when its inputs are: A is high and B is low and either input C or input D is also HIGH and make a sketch. Derive a Boolean equation that describes the performance of the required circuit.
Part 2
a) Using a ‘Logic Tutor' design and construct the circuit using the output connected to a LED or Logic-probe, and produce a four-variable truth table and apply allcombinations of input variables to the circuit and each time note the logical state of the output.
b) Demonstrate and test the circuit operation for your tutor.
Opportunity for distinction
You need to demonstrate that you have completed the assignment without support from your lecturer or peers. D2a