Remember to include an NI-845x SPI Script CS Low.vi in the beginning of your program to ensure that the active high functionality is implemented. This is due to the chip select initially being high in value, which is remedied by setting the chip select low after your initial VIs: NI-845x SPI Create Script Reference.vi, NI-845x SPI Script Clock Polarity Phas.vi, NI-845x SPI Script Clock Rate.vi, and NI-845x SPI Script Enable SPI.vi. This should be done for each chip select you plan to use to regulate communication to devices as described in Setting Multiple Chip Selects on the NI USB-845x
The script API VIs are located in the NI-845x » SPI Advanced palette.
Please download the attached file for a complete example.