The following are a set of links to websites and resources that I think are valuable or interesting. The topics and links are listed in alphabetical order. Critically, every link I include here is to a resource that is freely and legally available.
Communication Systems
Introduction to the Controller Area Network (CAN) - Steve Corrigan
Optimisation
Engineering Design Optimisation - Joaquim R. R. A. Martins and Andrew Ning
Radio
Fraction/Integer-N PLL Basics - Curtis Barrett
High Frequency VCO Design and Schematics
PLL Performance, Simulation, and Design - Dean Banerjee
Security
Hacking washing machines - Hajo Noerenberg and Severin von Wnuck-Lipinski
Watch Your Kids: Inside a Children’s Smartwatch - Nils Rollshausen
Software Abstraction
Architectural Styles and the Design of Network-based Software Architectures - Roy Fielding
Designing abstractions with properties in mind - Ted Kaminski
Game Design Patterns - Robert Nystrom
The one ring problem: abstraction and our quest for power - Ted Kaminski
The Unreasonable Effectiveness of Constructive Data Modelling - Alexis King
Software Languages
Crafting Interpreters - Robert Nystrom
Keyword overloading: the static keyword - Jens Gustedt
Software Testing
Fuzzing vs property testing - Ted Kaminski