I am designing a peripheral data acquisition device that will communicate digitally to a PC via the DAQCard 6533. Data transfers are 8 bits wide and need to be in both directions. The 6533 technical reference manual states only that the user can choose the direction, ie input or output, of data. My application requires that the direction switches without manual intervention about every 100ms. It is not necessary that input and output occur simultaneously. Is it possible for this to happen under software control? If so can input and output occur from a single port (port A say), or would input and output signals have to be allocated to different ports?