Hello Pierre-Andre,

thank you for your help with the interrupt handling. To close this case I'll
attach my interrupt
handling code for the SIS 3100 to this post as a reference. Maybe someone wants
to do something
similar in the future. 

I've decide to go for a C++ frontend therefore it is a class that handles
everything. The user only
has to provide a function pointer to the constructor that handles the interrupt
bitmask. The
interrupt handling is done with a timedwait within a separate thread. 

Cheers,
Clemens

> Hello Clemens,
> 
> The hardware readout is triggered by the interrupt within this thread. The
main thread poll on  
> the data availability (from the rb) to filter/compose the frontend event.
> In a similar multi-threaded implementation presently used in a dark matter
experiment we start 
> as many thread as necessary to constantly poll on the hardware for "data
fragment" collection.
> The event composition is done in the main thread through polling on the RBs.
> 
> Depending on the trigger rate and readout time, we can afford to analyze the
data fragment at 
> the thread level and add computed/summary information to the ring buffer on a
event-by-event 
> basis. This facilitate the overall event filtering happening later on in our
event builder. 
> 
> "polling the trigger signal?", I don't understand. You can poll on the trigger
condition but 
> then you don't need interrupt.
> 
> The original Midas interrupt implementation was to let the interrupt function
set a acknowledge 
> flag which is picked up by the standard midas polling function (user code) for
triggering the 
> readout. This method ensure a minimal time spent in the IRQ and works fine for
a single thread.
> 
> In regards of the CAEN V1742, we do have a VME driver for it, but it hasn't
been added to the 
> Midas yet (quite recent), but please don't hesitate to send us a copy.
> 
> Cheers, PAA
>