Logic: Recording not starting immediately

[LarsB]

When I try to record (16 bits, 128 Mi samples at 50 MHz), WaveForms doesn't capture anything if I start the recording and then press stop after a second.

Why is there a delay before recording starts?  WaveForms states it's "Recording Prefill"?!  Can I avoid that?

Trigger is set to None.

 

[LarsB]

What message do I have to wait for?

If I wait for the box turn green and the message "Recording", then wait 1 seconds before I press stop, I only have captured a few ms.  Do I have to wait for "Recording Trig'd ...", even though I don't have a trigger set?

Or is there a limit to the sample rate when recording that WaveForms isn't aware of?

 

[attila]

Hi @LarsB

At rates above 1MHz the reading is only started after the capture is done. This, to prevent interference in the device DDRam read/write and caching.

[LarsB]

Thanks for the explanation!  I figured you really need to set a trigger to capture what you want.