Hello.
USB 6501 is software-timed. Have a look at these links :
USB-6501 Benchmarks with NI-DAQmx
Low-Cost Digiyal I/O Device for USB
SPI Digital Waveform Reference Library could generate waveforms with any National Instruments hardware-timed digital I/O device.
Have a look at this link :
SPI Digital Waveform Reference Library
In conclusion the SPI Digital Waveform Reference Library is not compatible with NI USB-6501.
Best Regards.
Romain D.
National Instruments France
