ROM Builder

A desktop tool for assembling, inspecting, and exporting ROM images for programmable memory ICs (EPROM / EEPROM / NOR flash), aimed at retro-computing projects. Take individual ROM dumps, lay them out into banks on a target chip, and export a single binary ready to program.

Built in Rust with eframe/egui.

Features

• Bank layout — divide a target IC into linear banks of a chosen ROM size (4k–512k) and place ROMs into them.
• Multi-ROM per bank — drop a ROM smaller than a bank and fill the leftover space with more ROMs as indexed sub-slots (0, 0.1, 0.2, …).
• Target IC catalog — common UV EPROMs (2716–27C080), Winbond reusable EEPROM-types (W27Cxxx), parallel EEPROMs (28C/AT28C), and NOR flash (SST39SF, Am29F, AT29C); pick by size or from a filterable IC list.
• Bank map — color-coded grid (unused / filled / duplicated) with a legend and pagination.
• Duplicate detection — banks/slots sharing a checksum are highlighted.
• Hex preview — paged hex view of any populated bank.
• Name suggestions — propose names from printable strings inside a ROM.
• Add ROM handling — exact-size ROMs drop straight in; larger ones can be trimmed or spread across banks; smaller ones keep the free remainder.
• Safety prompts — confirmations (with Enter/Esc shortcuts) before clipping to a smaller chip, splitting/consolidating on a layout change, removing banks, or quitting with unsaved changes.
• Projects — save/restore the full editing state as a .romproj file.
• Export — write the chip-sized .bin plus a .metadata.txt summary.

Build & run

Requires a recent stable Rust toolchain.

cargo run            # build and launch
cargo build          # debug build  -> build/debug/rom-builder.exe
cargo test           # run unit tests

(Build output goes under build/ via .cargo/config.toml.)

Usage

The app starts with only New Project, Open Project, and About available; everything else turns on once a project is active.

1. New Project (Ctrl+N), then pick a ROM Layout size and a Target IC.
2. Add ROM (or double-click a bank) to place ROM files into banks.
3. Manage banks in the list: rename, suggest names, replace, extract, remove.
4. Save (Ctrl+S) / Save As the project, and Export Binary (Ctrl+E) to produce the file for your programmer.

Keyboard shortcuts: Ctrl+N/O/S/E for New/Open/Save/Export; Enter/Esc to confirm/cancel dialogs.

Project files (.romproj)

A .romproj is a zip archive containing each populated bank's binary (banks/bank_NNN.bin) and a project.json describing the chip, layout, pad byte, UI settings, and per-bank slot layout (names, lengths, source paths). This preserves sub-slot boundaries and names across sessions.

Exported output

Export Binary writes a raw, chip-sized .bin (banks placed linearly, the rest padded) and a .metadata.txt sidecar with per-bank offsets/checksums and a machine-readable slot layout (used to reconstruct sub-slots if the .bin is re-opened next to its sidecar).

Notes & limitations

• Direct device programming is not implemented — export the binary and use your programmer.
• Re-dividing the layout to a different size preserves the bytes but not the per-bank names/sub-slots; prefer saving a project to keep those.

License & credits

• Licensed under the MIT License.
• Author: ArleyJR.
• Built with eframe/egui (dual-licensed MIT or Apache-2.0); file dialogs via rfd; project files via zip and serde_json.
• Application icon: Puzzle icons created by Freepik — Flaticon (https://www.flaticon.com/free-icons/puzzle).