With new microcontrollers, almost everything has moved onto the chip itself. The "EE" perspective (the surrounding circuitry) is little more than following the

With new microcontrollers, almost everything has moved onto the chip itself. The "EE" perspective (the surrounding circuitry) is little more than following the datasheet and observing the rules for routing. Sparkfun is awesome not only because they sell cool things, but because they release many of their schematics, check this one out - https://www.sparkfun.com/products/11113 https://www.sparkfun.com/products/11113 (click 'schematic' or 'eagle files' (if you don't have eagle, you'll need that too - http://www.cadsoftusa.com/) http://www.cadsoftusa.com/)). You can see all the pieces needed to make an 'Arduino'. A voltage regulator, a reset switch with a pull up resistor, some filtering capacitors, and a crystal oscillator. That's it. If you make a board yourself that runs off of a Lithium battery, you don't need a voltage regulator, might not need a reset switch, you can use the internal oscillators, and you have almost nothing outside of the microcontroller. It's really amazing. I don't think you meant 'EE perspective' this way, but if you meant getting closer to the machine code, one thing you can do and still be able to do everything nice is rip open the Arduino source code, or re-implement the functions they provide. Try rewriting digitalWrite(PIN, STATE), or analogRead(PIN), and see how many instructions those functions need.