Is this problem not simply due to both the adafruit 2.8 and Hifiberry both using GPIO 18 and as such causing the conflict ?
Adafruit uses GPIO 18 for one of the four switches and Hifiberry uses GPIO 18-21 for sound output ?
Certainly this is the case for DAC+ and to quote from Hifiberry site „GPIO’s 18-21 (pins 12, 35, 38 and 40) are used for the sound interface. You can’t use them for any other purpose“.
I currently use a headless B+ pi with Hifiberry DAC+ running Volumio without issue and the sound is so much better than anticipated but I want a touchscreen so I have just ordered a Pi 3 and Adafruit 2.8″ because it is supposed to run under M2P (not supported under latest Volumio)
My plan is to mount a Piface Shim under the DAC+ to duplicate the GPIO header, connect the Adafruit via cable as it will be panel mounted but omit GPIO 18 and hopefully it should work ???
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