question about reading from external memory while providing clock signal

[Evan A Young]

I'm trying to figure a way to provide a clock signal (~200kHz) and synchronously read digital lines at the same rate. It will be used to read from a memory chip of a data logger. It seems that using software timing would be too slow.

I have to use the DAQCard-6533 because of hardware restrictions. I can slow the whole process down, but I must keep it within reason, as the acquisition time is limited as well.

[Spencer S.]

Evan,

I agree that using software timing is not appropriate for this application. You will want to perform a pattern input operation. I would suggest that you examine the LabVIEW examples Buffered Pattern Input.vi and Cont Pattern Input.vi. The first demonstrates the programming structure you will want to implement for a finite acquisition and the second for a continuous acquisition. If the clock source input is set to "internal", the appropriate REQ line will output the clock at the frequency specified by the clock frequency input. Below, I have included a link to a KnowledgeBase with other pertinent information:

Configurin
g the REQ Clock Output Pin for an NI 653X Device

Good luck with your application.

Spencer S.