On 01/19/11 08:53, Girisha SG wrote:
>
> If I register an interrupt handler using
> InterruptAttach/InterruptAttachEvent calls to each of the SDMA
> channels whenever they are created, is it necessary for me to use
> InterruptWait seperately for each channel ?
> If I can attach multiple ISR handlers(or same ISR for each channel)
> one for each channel In the main thread how will I get to know for
> which channel interrupt has been generated(so that InterruptWait got
> unblocked) ?
>
> Also if I want to attach an ISR for a DMA channel and the thread dies
> & later on every thing will get managed in ISR ....
> can I do something like this(i.e. there is no InterruptWait call & DMA
> transfer is enabled & left. It runs till somebody disables the DMA
> transfer). Does it make 
sense & can I do this ?
>
> Also if I get piece of code to understand this will be very helpful
>
>
>
> _______________________________________________
>
> General
> http://community.qnx.com/sf/go/post82474
>

Hello,

The following online documentation provides a few examples for you:

http://www.qnx.com/developers/docs/6.5.0/index.jsp?topic=/com.qnx.doc.neutrino_prog/inthandler.html

To answer your questions:

1. You only need to call InterruptWait() once to service multiple
threads (like calling MsgReceive() from a thread in order to service
multiple requests from other threads/processes). The documentation above
recommends using a dedicated thread to handle any interrupt specific work.

2. While the ISR is running - nothing else can execute (unless I think
the target is a multicore) so you can not kill the thread. Basically the
ISR will run until it is done. Now I am not sure what would happen if
after the ISR finished and the event was sent out to unblock
InterruptWait() but the thread that was waiting died. I believe the ISR
event will reach the thread before any cancellation can occur...Testing
will tell though.