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"Harbaugh, John S" <[log in to unmask]>
Reply To:
Harbaugh, John S
Tue, 28 Sep 1999 14:20:46 -0700
text/plain (36 lines)
> ----------
> From:         > Íhlund Magnus[SMTP:[log in to unmask]]
> Reply To:     Íhlund Magnus
> Sent:         Tuesday, September 28, 1999 12:58 PM
> To:   [log in to unmask]
> Subject:      Real time problem
> Hi,
> I am struggling with the following problem:
> After Object ACC has received event RELEASE, then object ACC shall activate
> CONSENT and then wait for 800 ms and then deactivate CONSENT.
> This is a requirement in my specification. I am using Ada in a large project
> and can't find out how I am supposed to assure that the time requirement
> above is fulfilled. This is a safety critical system.
> I am looking in the Annex D (Real Time) but can't seem to find a secure
> solution.
Section D.2.2 and D.3 should help here.  Apply these pragmas to order the ready queue by priorities.  

> Maybe the delay until statement is a part of the solution, but how can I be
> sure that the ACC will deactivate CONSENT directly after those 800 ms ?
Make sure that ACC is a higher priority than CONSENT.  Following the delay expiration, ACC will be at the head of the ready queue and preempt CONSENT.  A simple delay statement should be adequate unless you need better resolution, or are executing cyclically.  

> Maybe interrupts is an alternative solution ??
> Thanks,
> Magnus Íhlund
> Celsius Aerotech
> [log in to unmask]