Hi,
There is no question.
First you need to know which interface (hardware) you need.
Then build this interface.
Then you need to know which interface parameters you need to use.
Then you need to know the protocol.
So go step by step.
Ask a detailed question. What help do you need. Don't ask global questions.
Give more informations. Where did you look for informations, what documents do you refer to, what did you understand, and what did you not understand.
Klaus