I've been happily using a Digi2 Pro with a Pi 4B and Spotify Connect for a few weeks. I decided to add a tri-colour status LED which I attached to GPIO17 (for power) and GPIOs 5, 6 and 13 for RGB. The LED worked fine with a simple Python program but now my HifiBerry Digi2 Pro card doesn't work i.e. no music. In-fact when using command aplay -l the card doesn't show as a device anymore. Have I fried it somehow? Are there any diagnostics I can do to see if it is broken or not?
My best guess is that you adding software that fiddles with the GPIO settings. Did you try again on a fresh installation without the GPIO stuff?
I purchased a new SD card and did a fresh installation as suggested, operating system upwards. My HiFiBerry Digi2 Pro is now working again, thank you for the advice :-) I had no idea that GPIO settings could persist through a power cycle! Am I correct to assume that the Digi2 Pro uses the same GPIOs as the Digi+ Pro? I haven't been able to find any information about the GPIO usage of the newer cards e.g. Digi2 Pro, DAC2 Pro, DAC2 HD etc. Thanks in advance.
It depends on what you're using. Some tools like pigpiod mess around with GPIO settings. Accessing GPIOs via the /sys filesystem should be completely reverted after a reboot.
Yes, the GPIOs are the same as on the Digi+ Pro.