Hello 6542User. I'm understanding your question to mean that you want to do a software initiated single read of the data lines (i.e. a static acquisition). Use the following functions from the NI-HSDIO driver:
niHSDIO_InitAcquisitionSession ()
niHSDIO_AssignStaticChannels ()
niHSDIO_ReadStaticU32 ()
niHSDIO_Close ()
There's a good example that ships with the driver that shows these functions being called:
..\niHSDIO\Examples\c\Static\StaticAcquisition\StaticAcquisition.c
Channels on the 6542 may be configured for static acquisition even when another data operation is in progress. For instance, you might be dynamically generating a digital waveform at 100MHz for hours, but still have a seperate section of code that statically reads the same channels without interrupting or affecting your generation operation. And in case you're wondering, the data is physically being sensed by the pin comparators - it's not merely checking what's currently in a software buffer.
I hope this helps,
Chris
