Description

One ROM was created by Piers Finlayson and is the most flexible ROM replacement for retro computers. The “Fire” version is powered by an RP2350 microcontroller and can be programmed via a USB port from the command line, web browser, or with a downloadable GUI studio.

• Based on inexpensive microcontrollers.
• Fast enough for Tandy, PETs, VIC-20s, C64s, 1541s, IEEE drives, etc.
• Same footprint as original ROMs – doesn’t overhang the socket like other solutions.
• JCM version uses flat blade pins: no square pins to ruin your sockets, or round pins that break easily.
• Quick Programming– build and flash in <10 seconds, no programmer required, program from your browser.
• Reflash in situ– no need to remove the ROM from the host when reprogramming.
• Software configurable chip select lines – no hardware jumpers required.
• Stores up to 16 images of different sizes and chip select configurations. Image selectable via jumpers.
• Replace multiple ROMS with one: a single One ROM can replace up to 3 original ROMs e.g. all of C64 kernel, BASIC, character set.
• Dynamic Bank Switching: switch between ROM images on the fly, e.g. different char ROMs.
• Hackable at runtime: change the ROM images being served and access telemetry from the ROM at runtime using AirFrog or other SWD probes.
• Images combined automatically: no need to manually build up your own larger PROM image containing multiple retro ROMs.

Visit the One ROM website or GitHUB project for more detailed information. Get support in the Discord channel!

One ROM emulates the 24, 28, 32 and 40 pin EPROMs and mask programmed ROMs used in nearly every computer-based system from the late 1970s through to the early 1990s.

ROM types replaced:

24 pin: 2704, 2708, 2716, 2732, 2316, 2332, 2364
28 pin: 27×64, 27×128, 27×256, 27×512, 23128, 23256, 23512, 231024, TCS531000
32 pin (coming soon): 27C010, 27C020, 27C040, 27C301, SST39SF010, SST39SF020
40 pin (coming soon): 27C400

Supported and tested systems include the Commodore 64, VIC-20, PET, 1541 disk drives, Atari 800XL, TI-99, CoCo2, BBC Micro and Master, PC XT, Amiga, arcade systems, and many, many more.

With One ROM you only need a single hardware variant to replace all ROM types with that pin count – 24, 28, 32 or 40 pin. All of the different ROM types are configurable, including the mask programmed chip select behavior. This means that whatever your system, One ROM has you covered.