I'm new to programming so don't know much I've been trying to connect the raspberry pi 2 and Arduino uno I've tried over USB with no luck no matter how many times I try to install the Arduino core and IDE when I download everything seems ok but when I try to compile code that I know is right it throws back lots of errors.
So I decided to try spi but not sure what pin is the SS pin I also need the code to make the raspberry pi 2 master