Customer:
How do I use the GPIOs on Inkplate? The documentation and examples only mention pins 9-15 (MCP23017_PIN_B3 to B7). How can I use the other GPIO pins in Arduino code?
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Originally submitted via email support on 28 January 2022. Migrated to the forum for community visibility.
Soldered Support:
You can use all pins from MCP23017-2 because all of them are free and we don’t use any of these pins for driving e-paper. On MCP23017-1 we use it for driving e-paper and other components, so you can’t use this from code without changing the library.
We provide an example for MCP23017 in our Inkplate library. When you use library functions for MCP23017, you write to the second MCP23017 (MCP23017-2) because we block writing to the first MCP23017 (MCP23017-1) since we use it for controlling the panel. If you write to pins on MCP23017-1, you could damage the panel.
Customer:
To use the MCP23017-2 GPIO pins GPA5, GPA6, GPA7, I would define them like this:
#define I2S_DOUT MCP23017_PIN_A5
#define I2S_BCLK MCP23017_PIN_A6
#define I2S_LRC MCP23017_PIN_A7
Soldered Support:
Yes, that is the correct way to use MCP23017-2 pins.