I'm using UniPi 1.1 Lite as developement board for larger project (which is based on UniPi Neuron) and I need to add RS485 bus to it. I can of course use USB dongle for this purpose, but I came across Waveshare's RS485 HAT for RPi. This HAT uses SPI (UART) for RS485 bus, which, to my understanding, should be unused on UniPi 1.1 Lite. But when I connect the HAT, the communication with RS485 bus seems not working.
It works when I connect the HAT to another RPi without UniPi connected, so I wonder whether the SPI pins (pin 14 and 15) from RPi are used somehow on UniPi? Acording to documentation, there is nothing about pins 14 and 15 (or I was unable to find anything).