is it poosible to directly power pi/any microcontroler from i/o pins
thanks
]]\alex
Hi Alex,
We are not sure we fully understand your question, so here is a possible answer. Let us know if we completely misunderstood!
Q: Is it possible to power a microcontroller from I/O pins (of another microcontroller?) ?
A: Short answer: most likely no!
A: Long answer: in most cases, the microcontroller to be powered will most likely require too much power for one (or more) GPIOs. For example, a typical AVR microcontroller such as the ATmega328 (the one used in Arduino Uno) can output up to 40 mA of current per I/O and cannot source more than 200 mA of total current for itself (see datasheet, page 313). Please note that are “absolute maximum ratings”, which means they would most likely damage the chip.
As you may already be aware, many microcontrollers use a lot more than 40 mA and therefore could not be powered properly by such small amounts.
Of course, there are some microcontrollers that can function very well with such low current, such as some advanced low power ARM Cortex microcontrollers (example). Such a chip could probably be powered with 5-20 mA (or one or two Arduino GPIOs!).
Sincerely,