Send numbers bigger than 256 by SPI
You need to send two bytes - a high byte and a low byte.

There are two things you need to know with SPI:


You must wait for one byte to finish transmitting before you send the next
The whole transaction needs to be wrapped with a digital chip select signal.


So you have:


Chip Select idles HIGH
You lower Chip Select
You send one byte
You send the other byte
You raise chip select


At the receiver you:


Wait for chip select to go low
Receive one byte
Receive a second byte
Chip Select rises
You combine the two bytes together into one integer.