Figure 1 - Verilog header containing constant definitions used across most of the files.
Figure 2 - Top module code
3 - Clock divider using 2 flip flops to divide the 100MHz input 4
times, outputting approximately 25MHz that was used as the VGA clock.
Figure 4 - Port and register definitions for Sync.v
5 - Initial states of bitmaps and registers. The bitmaps are all
initialized as shown, since Verilog doesn't allow block assignment for
Figure 6 - Logic control in Sync module that determines the next state of the program.
Figure 7 - Multiplexer for difficulty selection as well as logic control for what bitmaps are visible on screen.
8 - Code controlling VGA output. First block scans the pixels while the
multiplexer selects an 8-bit color for the selected pixel position
depending on if it overlaps any of the labels, logos, paddles, or ball.
Figure 9 - Port and register definitions for the BallController module.
Figure 10 - BallController.v Win/End conditions for the game, all logic in this module updates on posedge of move clock.
11 - BallController.v collision logic. Player paddle surface collision
needs adjustment somewhere, but not sure what exactly the adjustment
needs to be as of now.
12 - BallController.v velocity direction logic, had to add extra to
help debounce the ball collisions. Otherwise, the ball gets stuck along
the wall or AI paddle.
debouncing is the biggest problem in the code still. After trying
several methods, the problem still persists. Due to the nature of the
program it is difficult to tell whether the issue lies with debouncing,
which some methods to fix suggests yes, or if the problem lies with
detecting the ball collision itself. Since we used the exact same logic
initially, it may be that VHDL is doing something behind-the-scenes
that verilog does not or this is simply a result of how Verilog gets
written onto the Basys 3 board compared to VHDL. However, this doesn't
quite explain why, despite using the same detection logic, the ball
does not detect a collision with the player paddle's surface (but it
does detect collisions with the side of the player's paddle,
interestingly). The problem was slightly relieved by increasing the
clock cycle that drove the ball movement and collision detection,
however the resulting slow-down of the ball movement itself would make
the game be a bit too trivial. Though, despite these increases, the
ball would not detect a collision with the AI paddle. Due to previous
test runs, we do not believe the actual paddle boundary itself is the
issue, but considering the odd behavior of the player paddle surface
detection it is possible that this is the case. Our latest build
included a debounce module to be used to debounce the collision
Initially, we presented that we changed the RGB output to the 8-bit
3-3-2 format, but this change was reversed to the original 12-bit 4-4-4
RGB format as the VGA output being out of sync was the sole issue for
not being able to display the game on the screen.
13 - Debounce module implemented to attempt to correct velocity changes and collision detection.
Figure 14 - The debounce modules being implemented, as well as the intermediate values that are used to debounce.
Figure 15 - The revised logic using the intermediate values shown in Fig. 14.