265 CDM PYTHON GAME :: Quicker, easier and cheaper to make your own chip!

265 : CDM PYTHON GAME

Author: VINCE LUCES

Description: A hardware-rendered VGA Snake Game in Verilog with growing mechanics and dual keyboard/PMOD controls.

Clock: 25175000 Hz

This project implements a hardware-rendered Snake game targeting Tiny Tapeout using digital Verilog logic and a VGA display interface.

VGA Signal Generator: Converts the 25.175 MHz pixel clock into standard 640x480 @ 60Hz timing signals (hsync, vsync, video_on).
Coordinate & Grid Mapping: Maps the 640x480 resolution into a 20x15 cell grid (each cell is 32x32 pixels).
Snake Game Logic: Runs movement and game state logic on every frame tick (v_cnt == 480).
- Supports directional controls with anti-180° turn prevention.
- Handles body segment shifting across a register array.
- Detects collision between the snake's head and food to trigger dynamic length growth (snake_len).
- Pseudo-randomly relocates food upon consumption.
PS/2 Keyboard Decoder: Decodes serial clock (ui_in[4]) and data (ui_in[5]) signals from an external PS/2 keyboard to extract arrow key presses.
Pixel Pipeline: Determines color generation on-the-fly ("beam racing") without requiring an external frame buffer memory:
- Green: Snake head & body segments
- Red: Food block
- Blue: Playfield background
- Black: Blanking / Non-active display region

Select the Gamepad preset or click directly on the game preview canvas.
Use your keyboard's Arrow Keys (or ui_in[3:0] buttons) to direct the snake.
Drive the snake into red food blocks to verify growth logic.

Connect a Tiny Tapeout VGA PMOD to uo_out[7:0].
Connect a PS/2 Keyboard adapter to ui_in[4] (Clock) and ui_in[5] (Data), or connect directional push buttons to ui_in[3:0].
Provide a standard 25.175 MHz system clock to clk and release active-low reset (rst_n = 1).

VGA PMOD: Standard Tiny Tapeout 6-bit R2R DAC VGA PMOD (mapped to uo_out[7:0]).
Display: Standard VGA-compatible monitor accepting 640x480 @ 60Hz.
Input Device: PS/2 Keyboard or directional push buttons wired to ui_in[5:0].

#	Input	Output
0	Button Up	R1
1	Button Down	G1
2	Button Left	B1
3	Button Right	VSync
4	PS2 Clock	R0
5	PS2 Data	G0
6		B0
7		HSync

Input

Output

Bidirectional

Button Up

Button Down

Button Left

Button Right

VSync

PS2 Clock

PS2 Data

HSync

Chip location

265 CDM PYTHON GAME