tranZPUter project enables drop-in vintage CPU replacements using RP2350B

The tranZPUter project, described as a 'transformable ZPU Computer,' provides a method for replacing obsolete integrated circuits in vintage computing hardware with modern silicon. By utilizing FPGAs or microcontrollers, the project creates drop-in replacements for various legacy architectures, including the Z80, 6502, and 6809.

One specific implementation, the Pico6809, targets systems like the Dragon 32/64 by replacing the original Motorola 6809 MPU. This hardware solution leverages the RP2350B microcontroller and includes an ESP32 co-processor to provide modern functionality such as virtual floppy drives, cassette emulation, and network connectivity.

Technical implementation of the Pico6809

• Core Processor: Utilizes the Raspberry Pi RP2350B microcontroller to emulate the 8-bit Motorola 6809 architecture.
• Peripheral Emulation: Employs the RP2350B's Programmable I/O (PIO) blocks to handle timing-critical legacy interface requirements.
• Co-processing: Integrates an ESP32 co-processor to manage extended features like networking and modern storage emulation.
• System Expansion: Offers modular support for virtualized cassette and floppy disk devices to replace aging physical media in retro systems.

Why it matters

This project provides a sustainable path for the preservation of vintage computing hardware by replacing unproducible silicon with modern, programmable alternatives. It demonstrates how high-speed PIO peripherals in modern MCUs can bridge the gap between legacy bus timings and contemporary hardware.