As practice shows, beginners, having looked at many books, having tried their hand at programming, very often not so much enrich themselves with knowledge and skill as accumulate questions that cannot be answered. To use microcontrollers in amateur practice, it is enough to have a programmer and a ready-made file of the downloaded program. After loading the program into the microcircuit, it can be soldered like any other element of the electrical circuit. In this sense, there is no need to even think about how it all works. Works, and okay. And if it doesn't work?