Fantastic article, thanks for taking the time to write it up! I'm trying to learn about embedded systems at the moment and it feela like a super steep learning curve, really appreciate your post breaking everything down.

A little typo I think I spotted: ' So, to turn on our LED we want to set the BR8 field, and to turn it off, we want to set the BS8 field.'

Should this be: ' So, to turn on our LED we want to clear the BR8 field, and to turn it off, we want to set the BS8 field. '