Articles in the Projects category

  1. USB 1-Wire Bridge

    A long time ago, I built some projects using the (then) Dallas Semiconductor 1-Wire interface.

    Although this isn't an interface I generally use much today, I thought it'd be fun to build a USB to 1-Wire interface.

    However, when I started designing it, I realised that I could add a …

  2. HD44780 backpack (SPI and UART)

    Even though they're quite dated now, I often quite like using "HD44780" (or compatible) LCD modules in projects I build.

    They're fairly easy to drive, inexpensive and very readily available.

    However, there are a few attributes which are less convenient:

    • They need at least 10 I/O pins to use …
  3. PC104 Ethernet

    Overview

    When I was designing the PC104 Dragonball project, I wanted to design a simple (cheap!) PC104-based module to check I'd got the footprint and mechanical properties correct.

    This project is based around the RTL8019AS ISA Ethernet Controller. It's mostly very similar to a very typical RTL8019 reference design, but …

  4. Modular CPU Platform - MIPS processor card

    Overview

    I'm not certain why, but I've seen very few hobbyist projects based around the early MIPS processors.

    MIPS-1 is a very interesting architecture, for a few reasons:

    • Up until RISC-V, it was very heavily used as a teaching architecture in universities, so there's plenty of documentation available online
    • The …
  5. Modular CPU Platform - Update 1

    Overview

    It's been a while since I posted an update about the modular CPU project - here's the latest status.

    Main Board

    It can boot DOS!

    Not particularly well at the moment - the 8086 board isn't functional at the moment, so I'm using the MCL86 Verilog 8086 core. This works, but …

  6. An on-FPGA logic analyser

    Overview

    While I was debugging another project (an 80486GX processor board for the modular_cpu project), I found I needed a way to capture the internal signals of the FPGA. While some Lattice parts do support their "Reveal" logic analyser, I'm using the open-source Yosys based toolchain, so I can't use …

  7. A Modular CPU Platform

    Overview

    This project is nowhere near finished, but as it's taking up a lot of my free time at the moment, I thought I'd add a quick website update in case any of the work-in-progress ideas are useful.

    For a long time, I've been interested in processors, and as someone …

  8. A SuperIO PC104 card

    Overview

    This was a project to add a number of PC compatible devices in a PC104 form factor module:

    • PS2 Keyboard / Mouse
    • 2x Serial Ports (one of which supports RS485)
    • 1x Parallel port (supporting ECP and EPP)
    • Real Time Clock
    • Floppy Drive controller

    This project is based around the Winbond …

  9. A simple RJ45/RJ12 splitter

    To balance out the complexity of the last project, here's a very simple (but useful) project that doesn't have any active components at all.

    When working with telecoms equipment, it's very common to need to connect RJ45 (8P8C) or RJ12 (6P6C) connectors.

    Although it's possible to buy patch cables and …

  10. A 68K PC104 card, based on the DragonBall SoC

    From time to time I like building retrocomputing projects based on old CPUs, and I decided that the 68K would be a fun challenge.

    The "DragonBall" is a very interesting SoC based around a 68000, with some useful peripherals added:

    • IRQ controller
    • 2x UARTs
    • 2x SPI ports
    • LCD controller

    Additionally …