So..I am trying to understand what I am working with, getting back to basics.  Usually I follow instructions such as wiring diagrams without really understanding how they work. 

Here is a MCP23017 port expander connected to a BB Black, so I can understand more clearly the IO communications, pullup resistors, and a little bit of I2C.  Its really fun.  Unfortunately I can only do this with python for now; maybe later on I can have the time to review C again.

JondZ