This book explains, starting from the lowest level of software, how computer systems work, focussing on the microcontrollers that are embedded in many electronic devices, and illustrating every step with practical examples that readers can experiment with for themselves using the BBC micro:bit, an inexpensive ARM-based microcontroller board. Where other books about programming the micro:bit rely on a runtime library that insulates the programmer from the hardware, this one makes a virtue of explaining how the hardware works in detail, and enabling the reader to understand everything that is happening in the machine. After using machine language to explain what happens in the processor, the book moves on to show how programs written in assembly language or C can interact with I/O devices and react to external events using interrupt-based control. The need to manage concurrent events leads to the embedded operating system introduced in the last part of the book, where programs can have multiple processes that interact by exchanging messages.
Mike Spivey has 35 years of experience teaching computer programming to students at the University of Oxford, including functional, procedural and object-oriented programming in many languages, compiler construction, operating systems and formal specifications. His research interests include the relationship between functional programming, concurrency and the semantics of programming languages.