1. FPGA Breakout Atari 2600 Video Game FPGA Reproduction
Doug Cumbie, CpE MS
UCF Fall 2008
EEL 5772 – FPGA Design
Professor: Jooheung Lee
December 2, 2008

2. Atari Breakout
Developed and released by Atari in 1976 as a coin-operated arcade game
Originally designed by Steve Wozniak (Inventor of the Apple computer) using only discrete logic chips
Eventually released for the Atari 2600 video game system in 1978

3. Gameplay
Break bricks for points by altering the path of a moving ball with a controllable paddle
Avoid missing the ball and losing 1 of the 5 available lives
Destroy all the bricks across 2 levels for a total possible score of 864 points

4. FPGA Breakout Design Modules
Video Generation
User Input Controller
Internal Logic
Graphics Display
Collision Logic
Score/Lives Logic
Paddle and Ball Frame Counters
Ball Movement

5. FPGA Breakout Design Overview

6. Video Generation
Model graphics resolution after Atari 2600 native resolution of 160x192 pixels
Extends the 640x480 Pixel VGA Display Driver from Lab 2
Horizontal and Vertical Counters are scaled to create the appropriate pixel size and resolution
[7:0] Pixel_X = Hcount / 4;
[7:0] Pixel_Y = (Vcount >= 48) ? (Vcount-48)/2;

7. Graphics Display and Animation
Graphics are displayed by setting the appropriate pixel color for each object when the Pixel_X and Pixel_Y values are at a specific location
Objects include: Ball, Paddle, Walls, Bricks, Scoreboard
Animations are done by using an adjustable counter module, FrameCounter, for timing the positional updates of the ball and paddle
Paddle FrameCounter is fixed at 200Hz rate (5ms refresh)
Ball FrameCounter is adjusted based on the number of bricks remaining
108 to 95 bricks: 33 Hz (30ms)
94 to 80 bricks: 50 Hz (20ms)
79 to 20 bricks: 100 Hz (10ms)
19 to 0 bricks: 125 Hz (8ms)
Ball movement is varied by slope ΔY/ Δ X, and altered by colliding with different X-positions on the paddle

8. Collisions Ball collisions with objects reverses X or Y direction
Ball collisions occur at object edges (Top, Bottom, Left, Right)
Bricks (6 rows of 18 bricks – 108 total)
Brick collisions are realized by checking ball’s current position and a 108-bit brick state register
Bricks are only destroyed on a top or bottom collision
If a brick top or bottom collision is detected, the following actions are performed: if (BRICKS[18*yBallBrick + xBallBrick]) begin
// 1. Clear brick state
BRICKS [18*(yBallBrick) + xBallBrick] = 0;
// 2. Decrement total brick count
brickCount = brickCount - 1;
// 3. Alter ball’s motion
yBallDelta = -yBallDelta;
// 4. Update score
Score = CalcScore(Score, yBallBrick);
end

9. Score and Lives Logic
Number fonts are stored in a 16 bit wide x 140 deep Single Port ROM (predefined in a COE file)
Each digit has a unique ROM and values are displayed by painting gray pixels at the top of the screen for every logic ‘1’ in ROM
The 3-digit Score is contained in a 10-bit register
Score is converted to 3 BCD values for each digit (hundreds, tens, and ones place) by using a module Score3BCD

10. User Input Controller Provides input to the gameplay – moves paddle
Uses original Atari 2600 joystick
Hardware interface to Joystick: 9-pin male D-sub connector to Xilinx board’s I/O expansion headers
Joystick commands send logic lows
Verilog software module inverts commands

11. Demonstration…

12. Questions?