RTBox Sporadic Read Lag

1

Xiangrui and PTB Community,


I am having issue using the RTBox in an RSVP task that requires very quick reads. This is an example of the current process:


nEvents = RTBox('EventsAvailable');

if nEvents > 0

    % this deals with a fractional return which indicates receiving data

    while nEvents < 1

       nEvents = RTBox('EventsAvailable');

       WaitSecs(.001);

    end

    % once finished receiving data

    [t, events] = RTBox(); % also tried with [t, events] = RTBox(.001)


This lag in read (often a few seconds) only occurs sporadically, while other times, there is no lag (meaning the read occurs in less than a few milliseconds). Do you have any thoughts on the issue and how to eliminate all lag?


Thanks,


Brody DeSilva

The University of Alabama at Birmingham


2
If clock sync has not been done for 9 seconds, the following line 
[t, events] = RTBox(); 
will perform clock sync implicitly, which may take ~60 or ~300 ms, depending on latency timer.

If the lag is longer than ~400 ms, it is likely due to the problem reported by one of the users recently. 

 

Please update the matlab driver code at http://lobes.osu.edu/rt-box.php . It will remind you to update firmware, which I believe will fix the problem.

Please let me know it goes. Thanks,
-Xiangrui