Hi!What's the difference between 5V vs VCC Vs Vin?If I want to power the arduino with a 3.7V lipo, where do I connect it to?Where does regulated 5V power go?Which pin do I use for what?I'm making my own arduino compatible but the atmega328 had only VCC pins and no 5V or Vin so I became really confused. Can someone give me a really specific explanation of those 3 pins?Thanks!
The question suggests you have never heard of a data sheet and/or never read one.
All you have to do is open the 660 page datasheet ...]This of course was an Atmel datasheet, not an Arduino datasheet. People still land on this page and there are no answers yet.Boards generally have an onboard voltage regulator. Some of which can struggle above 150mA, especially for Nanos and Tinys. If you have a suitable supply, this can be bypassed.5V is normally *OUT*, used for things like I2C device power, but you can hook this up to a lower voltage battery, batteries will not have ripple or RF noise, but they may droop. Bear in mind anything relying upon regulated 5V as a "reference" will scale to your battery voltage.Vin may or may not be regulated, but should be above 5v for *further* regulation to 5V (nominally)Vin should generally be < 12V, probably no higher than 15V, depending upon the regulator and the upstream capacitor limits. The odd LM7805 regulator can cope with 35V, but the capacitor maybe only 16V. The higher the voltage the less efficient the regulation will be.Vcc is the DIP package supply, it should be 5V, whatever the source, but boards might range from 2.7V to 5.5V depending upon design and that datasheet.You should be aware of "Brown Out Detection" and disable it, or set it below your battery vor a oltage.Your results will be arguably better with a "Branded" board.For a 3.7v LiPo I would strongly recommend a 3.3V Nano type design, through the onboard regulator with a switch to prevent the battery from draining through the regulator when the board is quiescent.
I see no reason to be a condescending jerk nor doubt the skill level of the person who is asking the question. especially when there seems to be a confusion around Arduino and Amtel datasheets.
Did we ever get to the answer? @CryptFS - I agree with you. If there was a Google answer, shouldn't it be on this forum?