Low Level Devel Builds a Simple Microcomputer by Linking a WDC 6502 to the Raspberry Pi Pico
Blending the old and the new, this video walks through creating a simple 6502 micro by using the Pico as RAM, ROM, clock, and serial.
The Low Level Devel YouTube channel has published a video which merges the old and the new by connecting a Raspberry Pi Pico microcontroller with the classic MOS Technology 6502 microprocessor to create a compact 1980s-style microcomputer.
The MOS Technology 6502, designed by a Chuck Peddle-led team in the 1970s, was found at the heart of a range of computers and consoles throughout the 1970s and 1980s: Eight-bit Ataris, the Apple II, the Commodore 64, Acorn's BBC Micro, and the Nintendo Entertainment System (NES) all used the 6502 or its variants, to name just a few of machines driven by the device.
Now, YouTuber Low Level Devel has demonstrated how to use a Raspberry Pi Pico and its RP2040 microcontroller, launched last month as the first microcontroller and in-house silicon from Raspberry Pi, as RAM, ROM, clock, and a USB-serial interface for a simple 6502-based microcomputer.
The project centres around both the Raspberry Pi Pico and the Western Design Center 65C02, a modern incarnation of the original MOS 6502 which offers the ability to clock down to single-stepping for ease of debugging and demonstration purposes. The Pico serves to replace three core components of a microcomputer's design: The RAM working memory, the ROM which stores the operating code and any other software to run at boot-up, and the clock which drives the 6502 CPU.
The video tutorial walks through developing the interface between the two devices using the Pico C/C++ Software Development Kit (SDK), connecting everything together, and booting the system to run some simple programs, and is likely to be only the first in a series: "I'm thinking about maybe doing some more videos on just different interactions with that processor in the Pico because the Pico has so many GPIO output ports and it's only a four dollar microcontroller," the YouTuber concludes, "you really can't beat it."
The full video is now available, with links for the parts used, on the Low Level Devel YouTube channel.