Relay integration

[MarkHaysHarris777]

I will add to what pfeerick as said, that the PL10 GPIO04 pin(7) used for the s-pwm LCD back-light, is not really a compatible PI bus pin per se. Someone found in the manual that the PLx pins are on a different base address. So, you not only have to disable the s-pwm in dts (and the driver) but you also have to set the base register (again dts) for the PLx pins in order for pin(7) to be used on the PI bus with RPi.GPIO-PineA64.

I don't recommend that. Just don't use pin(7). All the rest of the PI bus pins should behave as expected.

Typically, I used either 180, 330, or 470 ohm resistors with GPIO pins, depending on the required ma for the load... you can use higher resistors for 3mm low power LEDs and you will need to use lower resistors for the 5mm higher power LEDs . I recommend using the 3mm low power LEDs .