IO Pi Plus behavior during boot?
The IO Pi Plus is a 32 channel MCP23017 GPIO expander for the Raspberry Pi
25/03/2017
Posted by:
areslagae
Hi,I am considering using a Raspberry Pi and several IO Pi Plus boards in a home automation system. The IO Pi Plus would greatly enhance the number of available outputs and inputs.However, since the IO Pi Plus board would permanently have electrically appliances connected to it (through opto isolators and 24V relays) I am wondering about the behavior of the IO Pi Plus during boot and startup of the Raspberry Pi and during configuration of the IO Pi Plus.Can onyone shed some light on this?Best regards,Ares Lagae
25/03/2017
Posted by:
andrew
The I/O pins on the IO Pi Plus default to an input state when the board is powered up so any optoisolators connected to the board would be switched off until the board is initialised.When using our python libraries and the other supported languages the boards are initialised with the pins as inputs with pullup resistors disabled.
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