Need help to use parallel port to control 8 digital potentiometers

Hi,
 
I would like to use LabVIEW 7.1 on a machine running windows XP to
control 8 digital potentiometers through the parallel port. The
following is a link to the data*** for the digital pots which should
be helpful for understanding my questions (I am using the 8 pin
version). Please see the Serial Interface and pin description sections.


http://rocky.digikey.com/WebLib/Microchip/Web%20Data/MCP41XXX_42XXX.pdf

Each pot needs to have a serial clock in, control signal in, and serial
data in. I understand how to use the parallel port to control the 8
different serial data lines for each digital pot, but I am not sure how
to control the other two signals needed by each digital pot. I think
using the strobe pin on the parallel port would be sufficient for the
serial clock input. The digital pot reads in its data on the edges of
the serial clock, and to my understanding the strobe pin changes with
each byte sent. Every byte sent through the parallel port would
correspond to one bit on each individual digital pot so I hope that
will work out. The control signal input is what I am not sure of.
According to the digital pots specifications, this signal needs to be
held low for 16 bits (8 control bits and 8 data bits) while sending
data, and data will not be passed if it is not low for a multiple of
16. I would like to use pin 16 of the parallel port as my control
signal, which to my knowledge is an output on the control register. I
have some questions about this. Can the control bits be set at the same
time as the data pits on a parallel port or does the address have to be
switched in between two such commands? How do I change the address so
that I can write to different registers for the parallel port in
LabVIEW? Can this be done with the Instrument I/O express VI?

I have already looked through many forum  and tutorial pages on
the parallel port but I have not found anything useful for my
application. Help!

Thanks,

Kurt
.

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