These pages contains simple experiments with esp8266 module and ESP8266 NONOS SDK. Everything here is based on accessing esp-12 with Debian system. I've got nothing else in my hands.
There is zillions of articles about ESPs on net, but yet there was problems - at least for me - to find simple answers how to operate module on very low level. Much of internet's articles replicate how to initially wire it. Articles that go deeper on how to really utilize it are based on NodeMCU or other facilitators - which of course by publishing higher level interface make it easier to program.
Personally for example using NodeMCU is bit "bloat" for my taste. I don't have background on electronics, but C is something I can write. For my taste high level APIs contains much of extra unneeded stuff when I'd really like to strip systems to bare minimum. To do just what is required, nothing else.
There is not very many articles about programming esp with C, so I collect my experiences in here. For me it needed bit reorientation and reverting back to times of Commodore 64 where you calculate clock cycles and to timings with asm NOPs.