May 2021
Running CP/M on the Raspberry Pi Pico microcontrollerThis article introduces CPICOM -- an emulator for CP/M 2.2 on the Raspberry Pi microcontroller.
Categories: retrocomputing, Pico, C, Z80
CP/M forty years on -- what it was, and why it still mattersWhy was the CP/M operating system so successful? Forty years on, why should we care?
Categories: retrocomputing, Z80
Why you can sometimes connect 3.3V and 5V I2C devices (and probably shouldn't)On websites, and in hobbyist kits for Raspberry Pi and Arduino, you'll often see I2C devices connected that have different supply voltages. This is (usually) safe and, in non-critical applications, tends to work. But why?
Categories: Raspberry Pi, electronics, embedded computing, Pico
Developing KCalc-CPM -- a scientific calculator utility for CP/MMy first CP/M program for nearly 40 years -- how, and why, I wrote it.
Categories: retrocomputing, C, Z80
Controlling a chain of MAX7219 LED matrices using C on a Raspberry Pi PicoThe MAX7219 IC is widely used to control an 8x8 matrix of LED, but they can be chained to create much larger displays. This article describes how the chaining works, and how to create a driver for the Raspberry Pi Pico.
Categories: software development, C, embedded computing, Pico
