ENG 2410 Digital Design LAB 7 Sequential Logic

ENG 2410 Digital Design LAB #7 Sequential Logic Design “Sequence Recognizer” Using both Schematic Capture and VHDL

Lab Objectives Ø Reinforce concepts we learnt about sequential circuits in class. Ø Understand sequential circuit design flow: Ø In this lab you will design a 4 -bit Sequence Recognizer using both: 1. Schematic Capture and 2. VHDL ENG 241/Lab #7 2

Sequence Recognizer Sequence recognizer is used to detect a specific pattern in a serial input. Ø You are required to design a circuit that detects the pattern “ 1101” Ø ENG 241/Lab #7 3

The Sequence Recognizer Steps: Ø Construct the state diagram of a Moore Machine. Ø Derive the state transition table. Ø Design the sequential machine using D Flip Flops. Ø Use Schematic Capture to enter your design. Ø Redesign using VHDL. ENG 241/Lab #7 4

Switch De-bouncing The switches and push buttons on the FPGA NEXYS 3 board might experience oscillations due to the nature of mechanical keys: One way to de-bounce a key is to introduce a delay until all the oscillations disappear. Ø We provide you with VHDL Code to solve the problem. Ø ENG 241/Lab #7 5

VHDL Code: Switch De-bouncing 1. 2. 3. 4. Create a new project (Call it Debounce. Module) Use the VHDL provided on the resources section on Lab #7. Synthesize the VHDL code and transform it into a symbol that can be used in any schematics The connectivity is as shown below: (Push Button on FPGA) push_bt Debouncing Circuit cclk (Clock on FPGA) Your Circuit debounce_out ENG 241/Lab #7 6

Lab Report Title Page – Group # and Names Ø Problem Statement Ø System Overview and Justification of Design Ø State Diagram Ø State Transition Table, Circuit, Schematic Ø VHDL Code (Include COMMENTS!) Ø l Sequence Recognizer Simulation Waveform Ø Problems Encountered and Recommendation Ø ENG 241/Lab #7 7

Academic Misconduct Reports and demos are submitted as a group, but it is a SINGLE group effort Ø You may talk with other groups but sharing codes or reports is NOT ALLOWED Ø Copying reports from previous years is also NOT ALLOWED Ø If we find copying we are REQUIRED to report it Ø 8