Single-chip microcomputer is the foundation, some people regard it as a tool (upstairs), others regard it as a ladder to a higher place (such as embedded hardware ARM, DSP, FPGA, operating system).
Spend a semester learning the basics first, and then reflect on your interests.
Find the simplest tutorial, read the first few chapters (if 5 1, it is enough to read IO, timer and UART, and don't read 803 1 and expand a lot of devices), learn to compile (at least understand), and read the grammar and routines of C5 1. Learn some basic peripheral circuits such as running lights, buzzers, digital tube scanning display, scanning keyboard, etc. (Hardware connection and C programming). The above is the most basic, about 3-4 weeks.
Buy a development board or weld one yourself, and try to write your own program. Such as communication protocol, digital-to-analog conversion, etc. See if you can write code according to the time sequence to let the microcontroller communicate with peripheral devices, such as some control (PID). ) algorithm, see if I can write it. (Note that the real world is analog and noisy, so it is not difficult to express many things in C language. But whether the reality can be realized is another matter, and we need to search more information on the Internet to see how others do it. )
Mode electricity mainly deals with triodes and operational amplifiers.
In terms of software, pay attention to standardization, maintainability (you will know when you come out to work later), efficiency (how to make full use of CPU), and learn the operating system when necessary (the so-called embedded system now means having an additional operating system).
One last suggestion: don't be superstitious about books, and soak in forums more.
Don't indulge in complicated theories.