Bare metal micro:bit – code for V2

This repository contains code for the experiments that are described in the book, Bare metal micro:bit, configured for the V2 micro:bit with an nRF52833 microcontroller chip.

Note than in August, 2024, I published a new revision of the code that uses a changed convention UART.TXD for referring to device registers, in place of the convention UART_TXD that was used before. This means changes to almost every source file, and will break any code that others have added to a fork of the repository. This won't happen again.

Each experiment has a separate directory containing all the files it needs:

Directory	Description
x01-echo	Building a program: Check that you can build and upload a simple program.
x02-instrs	Machine instructions: Investigate the effect of single machine instructions.
x03-loops	Loops: Write programs for multiplication and division that contain loops.
x04-numbers	Numbers: Explore number representations and conditional branches.
x05-subrs	Subroutines: Learn how to define and call subroutines to give structure to a larger program.
x06-arrays	Memory and arrays: Exploit instructions that load and store data in RAM.
x07-hack	A buffer overrun attack: Build a working (but harmless) model of a computer virus.
x08-heart	Digital input/output: Use device registers to control I/O pins and light LEDs.
x09-pureasm	Pure assembly language: Flash an LED with a minimal program written in assembly language.
x10-serial	Serial communication: Use a serial device to transmit characters.
x11-interrupts	Interrupts for I/O: Control the serial device with interrupts to free the processor.
x12-intrmech	Interrupt mechanism: Plot gaps in a waveform to measure the time needed to handle interrupts.
x13-neopixels	Neopixels: Use assembly language to make a bit-banged implementation of the protocol for WS2812 'NeoPixel' LEDs.
x14-processes	Processes: Use micro:bian processes to perform multiple tasks concurrently.
x15-messages	Messages: Use messages to communicate between processes.
x16-sync	Synchronisation: Synchronise the actions of multiple processes by making them exchange messages.
x17-drivers	Device drivers: Manage I/O devices using driver processes that receive interrupts as messages.
x18-level	I2C-based spirit level: Access the micro:bit accelerometer over the I2C bus to make a 2D spirit level.
x19-servos	Servo motors: Use a timer to generate the signals needed to control servo motors.
x20-radio	Radio: Communicate between multiple micro:bits using the in-built radio.
x21-car	Remote-controlled car: Use servos and radio to make a remote-controlled car.
x31-adc	Analog to digital converter: A device driver for the analog to digital converter.
x32-infrared	Infrared remote control: A program that uses GPIO interrupts to decode signals from an infrared remote control.
x33-clock	Neopixel clock: Software for a Neopixel-based clock.