Page 1 of 1

Odd behaviour of rp_Acq* functions from web app

Posted: Thu Jan 14, 2021 3:48 pm
by AlexLeoSchmid
Hello everybody,

When trying to implement a simple web app, that fills the ADC buffer after a trigger, I encountered the following issue:

If the server-side calls rp_App_Init() during the rp_app_init function, as recommended in the documentation, the FPGA's write pointer doesn't stop incrementing after the trigger has occured and the trigger delay has passed.
If the server-side calls rp_Init() instead of rp_App_Init(), the acquisition works as expected, just as described in this thread.

You can verify the issue yourself with this web app. Changing the initialization function to rp_App_Init leads to the write-pointer to never stop incrementing and the acquired data to not be sent to the client. I've been running this app on the STEM 125-10 with the latest OS.

So far, I haven't encountered any issues with using rp_Init instead of rp_App_Init, but is there any functionality you'd expect to break when using the wrong init-function? I can't tell what the difference is between them, because it doesn't seem like the source code for rp_App_Init is included in the official RedPitaya git repository.