Hi I have to reverse engineer/decode the communication on a two wire SPI bus, there is no slave select line to help determine master and slave. How do I determine which side is communicating at any point in time? I think I can determine which side is the clock with a couple of back to back diodes. But the data line is more difficult. I have tried diodes and series resistors but I have difficultly interperating the results. The difficulty comes from probable open collector drives for the data lines. What can I do?