A-ONE I/O Interface Board
8-bit input / output expansion for the A-ONE Apple-1 replica
Expand your A-ONE system with real hardware interaction. The A-ONE I/O Interface Board is a practical 8-bit input and output expansion card designed for the A-ONE Apple-1 replica platform. It allows users to directly read digital inputs and control external outputs from BASIC or machine code.
Visual and intuitive hardware control
The board features a clear and practical layout with:
  • 8 red LED indicators for output monitoring
  • 8-position DIP switch input bank
  • selectable I/O addresses via jumpers
  • direct A-ONE bus connection
Perfect for retro-computing experiments, education, and hardware prototyping.
How it works
The A-ONE I/O board uses memory-mapped I/O, just like classic 1970s computer hardware.

The DIP switch provides an 8-bit binary input value, while the LED row shows the output byte written by the computer in real time.
Operation (BASIC Example)
Write output value:
A = 128
POKE -24576, A
Read switch input:
B = PEEK(-24576)
PRINT B
Ideal for learning binary logic, low-level programming and hardware interfacing.
Features
  • Fully compatible with A-ONE Apple-1 replica boards or systems
  • 8-bit input and output interface
  • 8 LED output indicators
  • 8-position DIP switch input bank
  • Selectable I/O addresses
  • Direct edge-connector design
  • Designed and manufactured in the Netherlands
A-ONE is a modern replica system inspired by the 1976 Apple-1 computer. This product is not an original Apple product and is not affiliated with or endorsed by Apple Inc. Apple-1 is a historical reference used for compatibility and educational purposes only.