Recommended · for some experience
#7 Arrays and Pointer Arithmetic
Why people recommend it
Lesson from the Quantum Leaps embedded programming course, praised for clearly explaining GPIO address offsets and why read-modify-write sequences can clash with interrupts.
Watch for: Part of a longer course built around a TI Cortex-M4 board
In their words
This video succinctly describes why the read/modify/store has potential problems when it comes to interrupts.
Sam Hammamy on electronics.stackexchange.com, Aug 2018. CC BY-SA.