# Tools7800.com

> A comprehensive suite of free, web-based development tools for the Atari 7800 console, created by Eagle (Dariusz). All tools run entirely in the browser with no installation required. Designed for homebrew developers working with the Maria graphics chip, 6502 assembly, and MADS assembler.

## About

Tools7800.com is the home of "Game Maker by Eagle - powered by MADS assembler" and a growing collection of development utilities for Atari 7800 homebrew programming. The tools are built with deep knowledge of the Maria graphics chip architecture, TIA/POKEY audio, and the constraints of 6502 assembly development. Eagle is an active member of the Atari 7800 homebrew community on AtariAge forums.

## Game Maker by Eagle

The flagship tool — a comprehensive HTML-based tilemap and sprite editor for Atari 7800 160A mode development.

### Features
- 16x16 pixel tiles with tile indices 0-127 (tile 0 always empty)
- Variable-width sprites: 8, 12, 16, 20, 24, 28, or 32 pixels wide × 16 pixels tall (widths in multiples of 4)
- 8 shared palettes with 2 bits per pixel (2bpp) color depth
- Free sprite placement on the tilemap canvas
- Tilemap grid: 10 columns, up to 999 rows (default 128)
- 16-frame tile animations arranged in 4 directional rows (4 frames per direction)
- Atagle command system with Y=0 bottom positioning for direct Maria DLL control
- Three editing modes: Tiles, Sprites, and Atagle (blue mode buttons)
- Undo/redo support (Ctrl+Z / Ctrl+Y)
- 20 default shmup sprites and 16 default shmup tiles included

### File Formats
- Native .eagle chunk-based save format (EAGLE magic header, versioned, chunks: CONF, PALT, TPAS, SPAS, SPWD, TMAP, TILE, SPRT, SMTA, PLSP, ATGL)
- SPWD chunk stores per-sprite width data
- JSON export/import
- MADS ASM export for direct assembly integration
- Maria 160B graphics format encoding support

### PNG Import
- Tile import: auto-picks best palettes, imports to indices 1-127
- Sprite import: best-fit to existing palettes
- "Skip odd pixels" option to halve source width for 160A double-wide pixel mapping
- CIEDE2000 perceptual color matching algorithm for accurate palette conversion

### Palette System
- PAL warm lum2 Trebor palette for accurate Atari 7800 colors
- 8 palettes shared between tiles and sprites
- Visual palette editor with real-time preview

## 7800sign Web Tool

A browser-based implementation of the Atari 7800 ROM signing algorithm. Signs ROM files so they will boot on real Atari 7800 hardware (the console requires a valid cryptographic signature).

### Features
- Implements the 7800sign algorithm originally by Bruce Tomlin
- Drag-and-drop or file picker ROM upload
- Supports standard ROM sizes and bankswitching formats
- Downloads signed ROM ready for flash cart or EPROM burning
- No server-side processing — all signing done client-side in JavaScript

## PNG to EMP Converter

Converts PNG images to Atari 7800 Maria graphics data with accurate color matching.

### Features
- CIEDE2000 color difference algorithm for perceptual color accuracy
- PAL warm lum2 Trebor palette support
- Handles Maria chip constraints (zone heights, DMA limits, palette restrictions)
- Outputs data compatible with MADS assembler

## MPT to RMT Converter

Converts MPT (Music ProTracker) format files to RMT (Raster Music Tracker) format for Atari POKEY sound chip music.

### Features
- Parses MPT module data structures
- Maps MPT instruments and patterns to RMT equivalents
- Preserves note data, effects, and timing
- Compatible with POKEY audio playback routines

## EaglePack Compression

A custom compression algorithm optimized for 6502 microprocessor decompression and VGM (Video Game Music) data.

### Features
- Designed for fast decompression on 6502 CPU
- Optimized for repetitive pattern data common in game assets
- VGM data compression support
- Small decompressor footprint suitable for ROM-constrained environments

## GUI File Browser for SD Multicart

A graphical file browser system for Atari 7800 SD-based multicart systems.

### Features
- Maria indirect mode graphics for efficient text and icon rendering
- Navigate directories and select ROM files
- Designed for integration with flash cart firmware
- Optimized for the limited RAM and display capabilities of the 7800

## Additional Development Resources

### Graphics Conversion Tools
- PNG to Maria 160A/160B format converters
- Palette optimization tools using CIEDE2000 color matching
- Sprite sheet slicing with Maria chip constraint awareness

### Audio Tools
- CMC/MPT tracker format utilities
- POKEY sound chip programming aids
- Polynomial noise generator configuration

### Assembly Development Aids
- MADS assembler-compatible output from all tools
- ROM filesystem architecture utilities for bankswitched cartridges
- Memory map visualization tools

## Technical Context

The Atari 7800 uses the Maria custom graphics chip, which operates differently from most contemporary hardware:
- Display List Lists (DLLs) define screen zones
- Each zone has a Display List (DL) of graphic objects (headers)
- Graphics modes include 160A (4 colors per palette, double-wide pixels), 160B (12 colors per palette), and 320 modes
- 8 palettes of 4 colors each (including transparency) in 160A mode
- Sprites and tiles share the same palette system
- The 6502 CPU runs at 1.79 MHz, dropping to 1.19 MHz when accessing TIA/RIOT

## Community

- AtariAge Forums: Eagle's "ASM MADS" thread — 600+ replies, 480k+ views (one of the most active 7800 programming threads)
- All tools are free and open for the Atari 7800 homebrew community
- Development powered by MADS assembler (Multi-pass Assembler for 6502/65C02/65816)

## Contact

- Website: https://www.tools7800.com
- AtariAge: Eagle (Atari 7800 Programming forum)