Hi Michael:
The LEGO MINDSTORMS NXT Driver (Fantom) has two main APIs: a C++ API and a G (LabVIEW) API. Using one of those would be ideal in most cases, but since CVI doesn't support C++, you're kind of stuck. Fortunately, creating a G API required us to create a C interface, and you should be able to use that for your development.
The Fantom SDK can be downloaded from LEGO's website
http://mindstorms.lego.com/Overview/NXTreme.aspx
Hope this helps!
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James Blair
NI R&D
