1. Implementation of Pong over VGA on the Nexys 4 FPGA
EECS 443: Digital Systems Design
Final Project Presentation
Austin Cosner and David Easley
5/3/2016

2. Presentation Overview
Project Introduction
VGA Tutorial
Project Implementation
Project Demo
Wrap-Up

3. Project Introduction Project Objective Advantages of Pong
Game using VGA
Advantages of Pong
Easy Implementation
Rectangular Objects
Basic Physics

4. VGA Tutorial Basic VGA Components H Sync (Horizontal Sync)
V Sync (Vertical Sync)
Colors
On the Nexys 4 Board
4 bits per color
RGB

5. VGA Tutorial
H Sync and V Sync Signal Explanation

6. VGA Tutorial Sync Signal Components Sync Pulse Back Porch Front Porch
Visible Display Area

7. VGA Tutorial RGB Signal Explanation 4 bits for each RGB Component
12 bit Color total
4096 Color Combinations
Creates a Voltage
0V to 0.7V
Color is sampled per pixel

8. VGA Tutorial
Timing Example Hz)

9. Project Implementation
7 Modules

10. Project Implementation (G1 : CLK Wiz)
Module 1 : Clocking Wizard
Xilinx IP
Found in IP Catalog
Operation
100 MHz => 40 MHz
Generate Pixel Clock

11. Project Implementation (G2 : VGA Contr.)
Module 2 : VGA Controller
Custom Design
Backbone Module
Operation
Create H Sync, V Sync and Video On Signals
Generate Signals and Pixel Counters

12. Project Implementation (G2 : VGA Contr.)
Main Process
2 Counters
Horizontal Counter Range
0 to 1055
Vertical Counter Range
0 to 627
Horizontal Visible
216 to 1016
Vertical Visible
29 to 629

13. Project Implementation (G3 : Pixel Gen.)
Module 3 : Pixel Generator
Custom Design
Backbone Module
Operation
Generate RGB Signals
Generate RGB Signals based on VGA Controller Counters

14. Project Implementation (G3 : Pixel Gen.)
Object Drawing
While the current pixel being drawn is within the bounds of an object, set that object to the “on” state
Constants (for permanent bounds) and signals (for movement)

15. Project Implementation (G3 : Pixel Gen.)
Color Selection Processes
Decisions made on a per-pixel basis
Aligned with the VGA clock
With-select-when dependent on what pixel is currently in question

16. Project Implementation (G3 : Pixel Gen.)
Paddle Movement
Reset to middle of side
Button press sends paddle up/down
Paddle movement signals used in ball reflection

17. Project Implementation (G3 : Pixel Gen.)
Ball Movement
Reset to center, starting velocity randomized (see random generator later)
Next state logic advancement at beginning of process iteration

18. Project Implementation (G3 : Pixel Gen.)
Ball Movement ctd.
Result of ball impact on paddle varies on paddle movement
Same direction movement = higher velocity ball
Opposite direction slows and changes ball’s vertical movement

19. Project Implementation (G3 : Pixel Gen.)
Ball Movement ctd.
Ball reflects off of the screen bounds and the wall based on current position

20. Project Implementation (G3 : Pixel Gen.)
Ball Movement ctd.
Prevent ball’s next position from going through the paddle or wall

21. Project Implementation (G4 : CLK Divider)
Module 4 : Clock Divider
Custom Design
Support Module
Operation
Create the Animation Clock
Used in:
Paddle/Ball Movement

22. Project Implementation (G4 : CLK Divider)
Main Process
Simple Counter
Generic Input Argument
Max Count Val
50% Duty Cycle
Count to Half

23. Project Implementation (G5 : State Mach.)
Module 5 : State Machine Contrl.
Custom Design
Backbone Module
Operation
Control the Game State and Internal Signals
Used in:
Scorekeeping
Object Reset

24. Project Implementation (G5 : State Mach.)
Basic State Diagram
Simple FSM, only three states
Returns to idle state upon reset signal
Point scored during game adds to count and returns to idle

25. Project Implementation (G5 : State Mach.)
Main Process
Basic case statement
State iteration through conditional signal assignment

26. Project Implementation (G6 : 7-Seg Contr.)
Module 6 : 7-Segment Controller
Custom Design
Support Module
Operation
Display the Score for the game on the 7-Segments
Used in:
Score Counter Output

27. Project Implementation (G6 : 7-Seg Contr.)
Main Process
With...Select MUX
Build Cathode String
Hardcoded Anode String

28. Project Implementation (G7 : RNG)
Module 7 : Random Number Gen.
Custom Design
Support Module
Operation
Create 2 pseudo-random numbers
Used in:
Velocity variation

29. Project Implementation (G7 : RNG)
Two Processes
Each process is triggered off of a different VGA clock
Pseudo random at its finest
Two counters for 6 states (0-5)
Mapped to speeds via with-select-when statements

30. Project Demo

31. Wrap-Up Future Work/Improvements 2 players Round Ball Variable Speed
Improved Input
Display Buffer

32. Wrap-Up
Thanks for listening!
Questions?