Design of "Tetris" based on FPGA

Time: 2025-05-21 11:54:29View:

Designing Tetris on an FPGA is an excellent project that combines graphics rendering, input handling, game logic, and finite state machines. Below is a complete overview of how to design Tetris for an FPGA — typically targeting platforms like Xilinx Artix-7 with VGA output and button inputs.

High-Level Architecture of Tetris on FPGA

pgsql

+-------------------+
|   Clock Divider   |  ← System clock to pixel/game timing
+-------------------+
         ↓
+-------------------+
|     Input Unit    |  ← Button or keyboard handling
+-------------------+
         ↓
+-------------------+
|   Game Controller |  ← FSM for Tetris logic
+-------------------+
         ↓
+-------------------+
| Block Generator   |  ← New Tetrimino logic
+-------------------+
         ↓
+-------------------+
|    Game Memory    |  ← Stores grid state
+-------------------+
         ↓
+-------------------+
|     VGA Driver    |  ← Outputs visuals to screen
+-------------------+

1. Inputs and Clock Management

Inputs: Use push buttons (left, right, rotate, down, start/reset).
Clock: Use a clock divider to generate slower game and VGA pixel clocks (e.g., 25 MHz for VGA 640×480).

2. Finite State Machine (FSM) for Game Control

Key states:

Idle: Waiting for start
Spawn: Generate new block
Fall: Move block down every interval
Move/Rotate: Respond to input
Lock: Freeze block when it can’t fall
Clear: Remove filled lines
Game Over

3. Block Generator

7 types of Tetriminoes (I, O, T, S, Z, J, L)
Represent each as a 4×4 matrix
Rotate using 90-degree matrix rotation or lookup table

4. Game Grid / Memory

Grid size: 10 (width) × 20 (height)
Store in 2D array or block RAM (BRAM):
reg [3:0] grid[0:19][0:9];
Update when blocks settle or lines are cleared

5. Input Handling

Debounce and interpret:

LEFT, RIGHT, DOWN, ROTATE, START
Can be done via FSM or counters to handle key hold durations

6. VGA Display Output

Use a VGA controller module:

Horizontal sync
Vertical sync
Pixel RGB output

Translate grid content into pixel regions (each block could be 20×20 pixels)
Color each block based on type

7. Optional Features

Score tracking
Speed increase with level
Sound (with PWM output)
Pause/resume

Modules Breakdown (Verilog/VHDL)

Example Modules:

Module	Function
`clock_divider.v`	Derives slower clocks
`debouncer.v`	Debounces button inputs
`tetris_logic.v`	Handles FSM, block logic
`vga_driver.v`	Generates VGA sync signals
`grid_renderer.v`	Maps grid to pixels
`input_controller.v`	Interprets user inputs

Display Mapping Example (VGA 640x480)

Use 10×20 block grid, each block 20×20 pixels
Leave margin on screen edges
Draw only active game area to VGA

Test and Simulate

Use simulation tools (e.g., ModelSim, Vivado) to simulate FSM and game logic.
Test block rotations, collision, and line clearing.
Visual testing via actual VGA screen or simulation waveform.

Tools and Requirements

FPGA Board (e.g., Basys 3, Nexys A7)
VGA Cable and Monitor
Vivado / Quartus Design Suite
Optional: PS/2 or USB keyboard module

Summary

Building Tetris on an FPGA is a full-stack hardware design challenge involving:

HDL (Verilog/VHDL)
Game mechanics
Graphics output (VGA)
Input management
Finite State Machines