Comment by riedel

My experience with microcontrollers is not up to date. Most of the stuff I did was 15 years ago.I remember, Espressif really disrupted the market. Things changed already with Advent of Arduino. Before that people wrote a lot of asm code inline and MCUs particularly from microchip had really good documentations (sure some quirks and errata always appeared later, but as I remember they found their ways into data sheets and application notes). Particularly as binary blobs e.g. for network appeared the API went from well defined hardware interfaces to libraries, etc. Today it is even common for some of those domain specific IC that typically rather contain an MCU that you have to sign NDAs to get access to documentation of some parts.