Corrupted output when using Play mode and logic capture

[AlanB]

As hinted at in: 

I am seeing an issue where a pattern that is sent to a Digital Discovery for use with Play mode occasionally ends up being corrupted, with a short section of it being repeated over and over.  I think this only occurs when also capturing digital signals at higher sampling rates.  The attached code is loosely based on DigitalDiscovery_PlayRecord.py, but reordered slightly and switched to use acqmodeSingle1.  Viewing the output on an external logic analyser, I can see that it outputs the expected pattern.  However, when I increase hzRecord to 400e6, I occasionally get the partial-repeat case - although the total length of the playback is the same as expected.  Is anyone seen this before, and able to suggest what I might be doing wrong?

test_play_2.py

[attila]

Hi @AlanB

With this setup you are reaching the DDRam bandwidth limit which is a bit above 800MBps.
In the test script the input would need 800MBps and the output additional 40MBps.

The normal digital-out/Patterns custom mode each DIO has 32Ki sample buffer.
If you only need up to this number of samples you don't have to use play.

[AlanB]

@attila Thanks, I understand - I'll keep the rates down in future.

My eventual use will likely require longer than the 32kiS limit of the normal mode, so I'm exploring the extents of the Play mode capability at the moment.