We are connecting Raspberry Pi3B with some MCP23S17 expanders: MCP23S17.
I have read that they could emulate an open-drain outputs, playing with high Z state of the pin when configured as input. What kind of input and output those GPIOs are?
What about when it is a normal output by default? are they push-pull? I have seen that they normally are push pull output.
I would like to use that for continuity detection between two pins that could be or not in contact. So I would like to know what kind of things I must to do or connect there, when I will do some of these things:
1.- Could I connect an output pin to another input, write the output pin and read the input pin value?
2.- Does I need a special "connection-configuration" for achieving this function propperly?
According what I have been seen, it seems to be "open-drain" the best option, due push pull option it's said that it can't be connected with other IC pins. I'm not sure about this information.
So if anyone could clarify me these questions will be helpful.