Connecting Interrupt Pins Directly to GPIO
The IO Pi Plus is a 32 channel MCP23017 GPIO expander for the Raspberry Pi
16/10/2017
Posted by:
RichieRogers
Hi,
I'm wondering if you can connect the INT pins directly to the RPi GPIO pins without a level shifter.
For instance, if the INT was configured as active low (would the pin be open state, then low or is it high, then low?)
Or if the INT was configured as open drain and the GPIO was configured with either pull up or pull down, would that work?
I just want to avoid having to have the extra wiring and pcb "floating around" just for two INT pins
Thanks,
Richie
I'm wondering if you can connect the INT pins directly to the RPi GPIO pins without a level shifter.
For instance, if the INT was configured as active low (would the pin be open state, then low or is it high, then low?)
Or if the INT was configured as open drain and the GPIO was configured with either pull up or pull down, would that work?
I just want to avoid having to have the extra wiring and pcb "floating around" just for two INT pins
Thanks,
Richie
17/10/2017
Posted by:
andrew
The INT pins can be configured as open-drain but I would not recommend connecting the INT pins directly to a GPIO pin without some form of level shifting. When the IO chips are first powered on the INT pins default to be an active high, active driver so until the Raspberry Pi is booted and the chips can be configured it would be outputting 5V into the GPIO pin.
17/10/2017
Posted by:
RichieRogers
I thought there must be a reason, thanks for confirming.
I'll get a level shifter.
Thanks,
Richie
I'll get a level shifter.
Thanks,
Richie
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