Introduction to Digital Design Lab Project

PC/CP 120

Digital circuits design

System Switch

))) a

b

F

Digital Fire alarm system

Combinational circuit:A digital circuit whose outputs

depends solely on the present combination of the circuit inputs’ values.

Turn on alarm (F=1) when smoke sensed (a=1) and system switch is on (b = 1)

F = a AND bBuild using logic gates AND

a

bF

DetectorDetector

Project Design StepsStep 1: Define the problem

– Describe the problem to be solved by the circuit (i.e. what it is supposed to do). What are the inputs and outputs.

Step 2: Logic design• Capture the function

– Create a truth table or equations, whichever is most natural for the given problem, to describe the desired behavior of the combinational logic.

• Convert to equations– If you capture the function with a truth table you will need to do this step.

• Simplification – Boolean Algebra, Karnaugh Map, ..etc

If any errors appear at any stage, revise earlier phases.

Project Design Steps

Step 3: Implementation– Create a circuit corresponding to the output's equation. Use logic gates –

AND, OR, NAND, NOR, XOR …etc– Draw a circuit diagram (or diagrams) of the circuit showing all connections and

gates to be used. – You will use Altera Quartus II to draw your circuit.

Step 4: Circuit Simulation– Demonstrate that the circuit performs as expected. – Choices made regarding what to simulate.– You will be using Altera Quartus II for the simulation.

If any errors appear at any stage, revise earlier phases.

Project Design Steps

Step 5: Prototype Test Results– Download your circuit to the CPLD board – Wire the input and output to demo your circuit.

Step 6: Demonstration– Demo your circuit to other groups in the class– Produce a poster showing your project steps .

• Poster should contain a brief description of your testing procedure, outlining any significant problems encountered along the way.

– Peer-to-Peer evaluation, 3% of project mark.

If any errors appear at any stage, revise earlier phases.

Propagation delay

• The time required for any signal transition to travel between pins and/or nodes in a device.

• The total propagation delay time through a logic circuit is a major consideration.

• Propagation delays are additive, so the more gates or inverters between input and output, the greater the propagation delay time.

Choose lab topic by next week.No duplicates

First come, first serve!Projects can be found on the

CP/PC120 lab page.