6502 SBC Rev 2 — Breadboard to PCB

In Progress Intermediate 6502 Computers Latest: v0.1.0
by Patrick · Apr 15, 2026 · 16 views · 2 followers · Est. cost: $45-60 · Est. time: 2-3 weekends · License: MIT
6502 breadboard homebrew KiCad retro SBC
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Links

</> GitHub Repository 📄 KiCad Design Files ▶ Ben Eater 6502 Series 📄 WDC 65C02 Datasheet 🛒 Buy on Mouser
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Overview

A minimal but complete 6502 single-board computer built from scratch. Started as a breadboard prototype, now moving to a custom PCB.

Goals

  • Run EhBASIC and a simple monitor ROM
  • 32KB RAM, 16KB ROM
  • 65C22 VIA for GPIO and serial I/O
  • USB-to-serial for terminal access
  • Clean single-board PCB layout

Current Status

The breadboard prototype is fully working. BASIC runs, serial works at 19200 baud via a MAX232 level shifter. Now designing the PCB in KiCad.

Design Notes

Address decoding uses a 74HC00 NAND gate — no GALs needed. The clock is a 1MHz crystal oscillator module. Reset circuit is a simple RC network with a tactile switch.

Power is 5V regulated via a 7805 from a 9V barrel jack. Current draw is around 150mA.