For example the ATMega32U2. Unfortunately you can’t plug this chip into a breadboard. But I’ve made a complete tutorial on how to build a circuit with it. It’s more for those beyond the very beginner stage, but if you’re curious check it out: https://www.build-electronic-circuits...
This should not happen, except for MCUs with a nominal internal reference voltage different from 1100 mV (e.g., ATtiny26, ATmega8, ATmega16, ATmega32, and ATmega8535). It may happen, if you do not connect AVcc and Vcc (e.g., on a ATtinyX61 and ATtinyX7). The most likely reason is...
This should not happen, except for MCUs with a nominal internal reference voltage different from 1100 mV (e.g., ATtiny26, ATmega8, ATmega16, ATmega32, and ATmega8535). It may happen, if you do not connect AVcc and Vcc (e.g., on a ATtinyX61 and ATtinyX7). The most likely reason is...