May 2021

Running CP/M on the Raspberry Pi Pico microcontroller

This 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 matters

Why was the CP/M operating system so successful? Forty years on, why should we care?

Categories: retrocomputing, Z80

C 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/M

My 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 Pico

The 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