There are two ways to integrate the SUB-20 multi interface adapter into the NI LabView environment. First method is well known - direct calling MS Windows dynamic link libraries (dlls), i.e in order to use the sub20.dll API you should create a SUB-20 LV driver by defining all the SUB-20 API function calls and their parameters. We have an example of "direct sub20.dll calls" method available for download from our SUB-20 web page. This example initializes SUB-20 i2c and SPI interfaces.
The second method is much easier but requires NI LabView version 7 or latter. Starting from version 7 the NI LabView supports the Microsoft .NET technology. If you have LabView v7 or latter, we would recommend you to look into the easier way i.e. using SUB-20 .NET component - sub20dnc.dll. This component is a part of the regular installation package and located in the bin subdirectory of your SUB-20 installation directory. You can download the latest software from our SUB-20 web page as well. Among other examples this package contains SPI & I2C LabView sample vi's.
see more info hereviewtopic.php?f=2&t=221viewtopic.php?f=2&t=120