Semtech driver RAK833


can I use RAK833 without use LoRaWan, only use the driver for semtech and use private protocol?



Surely, yo can use it as you want.
But we only supply the firmware and source code for LoRaWAN, if you want to use your private protocol, you need to customize the source code by yourself.
You can refer to our LoRaWAN source code for RAK833 + RPi.