the.com/gpio
a pin that has no opinion until software gives it one.
means a general-purpose input/output pin on a chip that software can configure to read a signal or send one, on demand.
from grew out of 1970s microcontroller design, where chip makers realized most pins didn't need a fixed job — they could be wired at will, so engineers started leaving pins blank and letting firmware decide, hence general purpose.
voltage logicusually just on or off, 3.3v or 5v
raspberry pifamous for its 40-pin gpio header
pull resistorsstop floating pins from reading garbage
not analogmost gpio is digital, not a dial
for instance
raspberry pi header — 40 pins, blinks leds since the 2012 model b
arduino uno pins — 14 digital gpio pins power a generation of hobby robots
esp32 boards — 36 gpio pins run cheap wifi-connected sensors worldwide