NI USB-6229 BNC outputting serial digital data on multiple lines tied to same clock through DAQmx

[123789]

I am using an NI USB-6229 BNC and attempting to use multiple DIO pins to send data out serially at a common but variably defined clock speed. I have been able to do this for one channel. However, I have been unable to sync other channels to the same clock. I understand that the DAQmx Sample Timing vi cannot be used in multiple cases when used as a “Sample Clock.” However, this places me in a confusing situation since using autostart with DAQmx Write in a loop runs at a frequency that comes from an unknown source (Windows timing?). The other option I considered was to use a single DAQmx Write vi with the 1d wfm nchan nsamp option. This however, seems broken in all cases (with context help showing the error in the attachments). I am at a loss as to how to proceed. If it helps any, I am attempting to use multiple digital lines to write out data serially which will go to three wire SPI input for a DA (TI TLV5616). There is a common FS (generated on a line as well) and common SCK with separate data lines for each of the DATA lines for each DA chip I have. Hopefully the problem is not equipment limitation. Thanks for any help that can be provided.

[Chris G in AE]

Howdy,

I'm afraid I'm not entirely sure of what you're trying to do with your application, but I can let you know why you're getting the error in LabVIEW.  You are trying to write a single digital waveform into an input that requires an array of digital waveforms.  This array of waveforms corresponds to the different data you'd like to output on each line.  For example, if you had 4 lines, you would need 4 waveforms of data to output.  I've included a picture of how to connect it so that DAQmx will accept the data.  Please post back if this doesn't work for you.  Have a great day!