Hello,
First, I would suggest reviewing the following example program that installs with NI-DAQ.
C:\Program Files\National Instruments\CVI70\samples\daq\di\DIdoubleBufPatternGen653x.PRJ
What I did was a simple modification to this program that writes the data to a file as it comes in. The format of the file will be that every eight bits contain a port�s information. If you have four ports then every four bytes is a single sample of the clock.
Good luck with your application!
Justin T.
National Instruments