[Tinyos-help] Detecting one event in another event

[Eric Decker]

I would structure this as follows:
The sendDone is async?  I believe so.  From sendDone, change your transmit
state to ACK PENDING (or
whatever you want to call it), post a task that starts the retransmit timer.
 If the timer expires fire off the send of
the retransmission.

In the receiver, if all checks out then change state appropriately and fire
off the task again which cancels the timer.

1ms is kind of tight.  how big are the packets and what is the transmission
rate.

eric

On Fri, Aug 1, 2008 at 3:55 AM, ram kishore <rapoliit at gmail.com> wrote:

> Hi,
>       The problem is exactly like this:
> ""When the message is send,send.done() event is generated.I start waiting
> for a packet to be received.If it doesn't come in 1ms,I will re-transmit
> else I will transmit the next packet.""
>
> *Coding part:*
>   In send.done ()
>   {
>              while ( timer <= 1000)
>          {
>               TOSH_uwait(1);  //wait for 1microsecond
>                 timer++;
>                if ( flag == 1)     //flag is a conditional variable;If
> packet is received,Receive.receive() event will set the flag to 1.
>                {
>                 call Leds.yellowToggle();
>                break;
>                }
>          }
> if  ( timer == 1001)
> post ResendTask();
>         return SUCCESS;
>
>   }
>
>
> I will transmit the next packet in receive.receive event.
> Conditional variable is not working in this regard.Any suggestion on
> different paradigm ?
>
> Regards,
> Kishore
>
> On Wed, Jul 30, 2008 at 11:54 PM, Eric Decker <cire831 at gmail.com> wrote:
> >
> >
> > On Wed, Jul 30, 2008 at 10:55 AM, ram kishore <rapoliit at gmail.com>
> wrote:
> >>
> >> Hi all,
> >>
> >> When ever a packet is received, an event ReceiveMsg.receive(TOS_MsgPtr
> >> Msg) is generated.Can I detect this in some other event for example in
> >> send.senddone() event,so that I can perform alternative task.How to
> >> detect it?
> >
> > First I'm not sure what problem you are trying to solve.  The description
> > you
> > give above sounds complicated.  If I understand correctly from the event
> > handler for send.senddone you want to check to see if a message was
> > received and do something else.  Is that correct?  If so it seems simpler
> > to let the different handlers handler their one thing.  Just an aside.
> > events are signaled from  another module and as such are pieces of static
> > code.  As such there isn't a way to detect an event in another event.
> > That said your alternative sounds like it might work but it depends on
> what
> > kind of events, async or not, are being used.  And as soon as you start
> > mixing
> > async stuff and wanting it to interact with a task level event things get
> > complicated
> > quickly.
> > eric
> >>
> >> An alternative to this may be using conditional variables.I declare a
> >> global variable "flag" as "false".Keep performing some task in
> >> senddone() event.when a packet is received,receive event generated
> >> will set the flag as "true", then I will stop doing task in senddone()
> >> event.Will this work?
> >>
> >>
> >> Best Regards,
> >> Kishore
> >> _______________________________________________
> >> Tinyos-help mailing list
> >> Tinyos-help at millennium.berkeley.edu
> >>
> https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
> >
> >
> >
> > --
> > Eric B. Decker
> > Senior (over 50 :-) Researcher
> > Autonomous Systems Lab
> > Jack Baskin School of Engineering
> > UCSC
> >
> >
>
>


-- 
Eric B. Decker
Senior (over 50 :-) Researcher
Autonomous Systems Lab
Jack Baskin School of Engineering
UCSC
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