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Advanced Digital Circuits ECET 146 Week 5. Professor Iskandar Hack ET 221B, 481-5733 hack@ipfw.edu. This Week’s Goals. Introduction to the concept of Hierarchical Design Techniques Designing a circuit with multiple projects. Hierarchical Design Techniques. Also called Top-Down Design
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Advanced Digital CircuitsECET 146Week 5 Professor Iskandar Hack ET 221B, 481-5733 hack@ipfw.edu
This Week’s Goals • Introduction to the concept of Hierarchical Design Techniques • Designing a circuit with multiple projects
Hierarchical Design Techniques • Also called Top-Down Design • A design technique that allows a project to be broken into a series of smaller projects • Each subdesign is developed and tested separately • The overall design is then assembled using either Text Design Techniques or by connecting the subdesigns in the graphical editor (preferred method for this course)
Design a four-bit full adder using Hierarchal Techniques • Create a project for FourBitAdder • Create a new Block Diagram File called ha.bdf • Enter Design for HA (find circuit in ECET 111 Book) • Create Default symbol (do not compile – you get an error) • simulate project HA • Create a new Block Diagram File called FA.bdf • Enter Design for FA (find circuit in ECET 111 Book) • Create Default symbol (do not compile – you get an error) • Create a new Block Diagram called FourBitAdder (this will be your top level design) • Insert a half adder and three full adders, and connect as done in ECET 11 • Simulate full design • These circuits can be found on pages 236-238 in ECET 111 textbook
Enter Design for Half Adder Half Adder • Enter the design using • Input • Output • XOR • AND2
Create Default Symbol • This step creates a schematic symbol that can be used in other designs
Full Adder • Repeat process for the Full Adder that you did for the Half Adder
Draw Four-Bit Adder • Open Graphical Editor and add the symbols ha and 4-fa’s and connect them as shown with inputs and outputs similar as shown on page 238 in Kleitz • Note – All files MUST be in the same directory on the drive!!! • Do not put ha, fa and fourbitadder in different directories.
Save, Compile, Define Device and Pins • After drawing the fourbitadder save it as a new file (fourbitadder.bdf) • Set as Top-Level Enity • Compile • Set Device as before to EP2C20F484C7 • Define input pins and output pins • Tri-State all unused Pins • Recompile after making assignments!!!
Simulation • Simulate as before (sample shown)
Simulate • Save the file as fourbitadder.scf and simulate Glitches because of propagation delays
Lab 4 • Implement an 4-Bit adder as discussed in Week 5’s Lecture • Simulate the design • Use SW0-3 for A and SW4-7 for input B • Output the sum on the LEDs • Either show the working project to the instructor or record a short video