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FlexRIO w/ 5761 ADC: How can I average consecutive large 'waveforms' using DRAM?

I am currently struggling to implement on-board averaging using DRAM on our FlexRIO system (PXIe-1082, PXIe-8133, PXIe-7965R, 5761R) - any help would be appreciated. I have LV 10 and did install the DRAM compliation bug fix found here.
What I want to accomplish

FPGA vi:
- Read in data from the 5761R at 100 MS/s with the 7965R (I16); use either external or internal clock
- Sum consecutive frames of data samples on the 7965R using DRAM (a frame is typically ~40'000 samples, but could go up to 1e6); max num of summed frames should be large (use I32)
- After a pre-set number of summed frames, write the summed data frame to DMA FIFO
- Start over

Host vi:
- Read summed data frame from DMA FIFO
- Save / process / display / ...
- Start over

There should be no deadtime (ie. no lost data points), but I don't care about latency.
I also attached the current status of my (unsuccessful) attempt, which compiles but generates invalid data (tested with a signal generator).


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Hi Fabrizio,



I wanted to let you know that we have a dedicated community portal for NI FlexRIO-related applications. The link to that community is:


This is be a better place to post NI FlexRIO questions as you can get better assistance through this resource.


Additionally, I noticed that you created an E-mail SR (7315913) today about the same issue, so one of our other Application Engineers will be contacting you directly very soon to address this issue. In fact, it may not be necessary to post on the FlexRIO community if you have already created an SR with us.



Eli S.
National Instruments
Applications Engineer
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