Engineer Shrinks Atari 800 to Tiny FPGA Module
In 1979, Atari’s 400 and 800 home computers introduced custom graphics and sound chips, four joystick ports, serial I/O resembling modern USB, and advanced gaming capabilities for the era. Priced at $549 and $999 respectively, these machines defined consumer-friendly personal computing. Now, 46 years later, Polish engineer Piotr “Osa” Ostapowicz has condensed the entire Atari 8-bit architecture into a module just 2×1.5 cm—roughly the size of a postage stamp.
Historical Context and Significance
The Atari 800 platform pioneered modular design with a CPU, video, audio, and I/O all on user-accessible slots. This flexibility fueled a vibrant software and hardware ecosystem. In Eastern Europe, especially Poland, Atari machines became symbols of technological freedom, sold through Pewex stores despite Cold War embargoes.
Atarino Project Overview
- Reimplementation of Atari XL/XE architecture on a single Lattice UP5K FPGA.
- Includes 6502C CPU core, ANTIC and GTIA video chips, POKEY audio, and memory controllers.
- Module dimensions: 20 × 15 mm, less than a Polish 1 Grosz coin.
- Clock speeds up to 31 MHz (original: 1.79 MHz), enabling faster software execution and new features.
Technical Deep Dive
6502C Core and Instruction Extensions
The FPGA-based 6502C core faithfully reproduces the original MOS Technology pinout and timing. Ostapowicz has added undocumented opcodes and extended addressing modes, allowing developers to write high-performance routines inaccessible on the stock 6502.
Memory Architecture and DMA Improvements
Unlike the classic “cycle stealing” whereby ANTIC halts the CPU to fetch display data, Atarino uses independent dual-ported SRAM blocks. This parallel memory architecture eliminates contention, boosting throughput by over 5× in graphics-intensive scenarios.
Video and Audio Enhancements
- Functional clones of ANTIC and GTIA with extended text and bitmap resolutions up to 640×480.
- Standard VGA output at 60 Hz and HDMI encoding for modern displays.
- POKEY audio emulation refined to cycle-accurate timing; ongoing work adds full asynchronous serial FIFO behavior.
FPGA Implementation Details
Atarino uses a Lattice iCE40UP5K FPGA, chosen for its low power, small footprint, and open-source toolchain. The project leverages ICEcube2 synthesis and Yosys for HDL compilation, while routing and bitstream generation rely on NextPNR. Ostapowicz contributes improvements to the open-source ecosystem, publishing VHDL modules under MIT license.
Enhanced Performance and Modern Features
Atarino runs legacy software unmodified but also supports:
- Memory-mapped SPI flash for on-board cartridge images.
- Ethernet MAC and Wi-Fi modules via SPI bus for networked demos and IoT use cases.
- USB-to-UART bridge for keymaps and serial console access.
“Achieving cycle-accurate emulation at 31 MHz on a 5 K LUT FPGA is non-trivial. The parallel SRAM banks are a game changer,” says Dr. Anna Kowalska, FPGA specialist at Warsaw University of Technology.
Applications & Future Developments
Ostapowicz envisions Atarino powering:
- Portable retro gaming handhelds.
- Educational IoT platforms teaching 8-bit assembly.
- Embedded systems where tight real-time control benefits from cycle-deterministic 6502 cores.
He’s refining POKEY emulation, expanding the development toolchain for CC65 and Visual Studio Code, and plans to ship complete kits with PCBs, 3D-printed cases, and extensive documentation.
Community & Preservation Initiatives
Poland’s Atari fanbase organizes annual retrocomputing meetups. Atarino’s open design encourages preservationists to build hardware archives, test niche software, and develop new hardware add-ons. The project is hosted on GitHub with community contributions under active review.
European Atari Legacy
During the 1980s, Atari’s reach into Eastern Bloc countries—facilitated by Polish-born Jack Tramiel—created a lasting legacy. Atari 8-bit machines introduced many to programming and digital art. Atarino reignites that enthusiasm, showing how 8-bit architectures can still inspire innovation.
Tags: FPGA, Atari 800, Retrocomputing, 8-bit, Embedded Systems