I forget to mention that I am trying to implement as much state machine logic as possible outside of the Pic processor. For the negotiation and signal controls. What will happen, is when I write or a read signal is detected, it will set the BUSY signal immediately. Then on the interrupt pin of the pic, it will process the data and clear the busy signal when done. Regards, James -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.