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Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
@allObjects
Most MPUs have kind of an 'outo-pin-mode': for no - and obviously some particular pin mode - settings, writing (a particular value) to a pin makes it an output, and reading from it makes it an input... It can be confusing at some times, but smartly applied, it reduces the amount of code and circuitry... It all depends how the output/input pin hareware registers are set and configured and are wired. The setup allows to have have them independent.
With open-drain is like bipolar open-collector: only hight / logical 1 matters from a driving / output point of view, and low / logical 0 behaves like tri-state. Said so, the input is driven be the outside and can be either high / logical 1 or low / logical 0. If the pin line is connected to a bus like line and is 'terminated' - pulled in either direction - with a 'weak resistor', it works quite neat for the one-wire setup.