Re: Interrupts: can be lost?

From	pozz <pozzugno@gmail.com>
Newsgroups	comp.arch.embedded
Subject	Re: Interrupts: can be lost?
Date	2020-07-13 08:35 +0200
Organization	A noiseless patient Spider
Message-ID	<regvan$fic$1@dont-email.me> (permalink)
References	<re2thr$ke8$3@dont-email.me> <aebz0xy5gryy$.kfehj4cltbc9$.dlg@40tude.net>

Show all headers | View raw

Il 11/07/2020 12:12, dalai lamah ha scritto:
> Un bel giorno pozz digitò:
> 
>> https://www.safetty.net/download/pont_pttes_2001.pdf
>>
>> Page 13
>> Note carefully what this means! There is a common misconception among
>> the developers of embedded applications that interrupt events will never
>> be lost. This simply is not true. If you have multiple sources of
>> interrupts that may appear at ‘random’ time intervals, interrupt
>> responses can be missed: indeed, where there are several active
>> interrupt sources, it is practically impossible to create code that will
>> deal correctly with all possible combinations of interrupts.
>>
>> Those words are incredible for me. I suspect I didn't get the point of
>> the author. I don't think that interrupt events on modern microntrollers
>> can be lost in some circumstances.
> 
> I don't know 8051, but every MCU I've ever used had interrupt flag
> registers. When an interrupt comes a flag is set, and then until you don't
> reset this flag (generally within the ISR) the subsequent interrupts on the
> same source are ignored. Therefore it is true that subsequent interrupts on
> the same source can be lost if they are too close [1].
> 
> But if the interrupts are different, this is not true. Two different
> interrupts events can come even at the exact same time, and both will be
> flagged. Of course they won't be serviced at the same time (unless you have
> a multicore CPU, maybe) but they will be "queued" and processed one at a
> time.
> 
> [1] Actually I think that there are some MCUs that have a counter instead
> of a flag for each interrupt source, and therefore they can queue multiple
> interrupts of the same source before they are processed. Then each call of
> the ISR will decrement the counter.

This is exactly what I thought when reading that sentence in the book.

Back to comp.arch.embedded | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 00:38 +0200
  Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-08 09:11 +1000
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 08:13 +0200
      Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 09:13 +0200
  Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-07 16:14 -0700
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 08:16 +0200
      Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 06:55 -0700
  Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 09:02 +0200
    Re: Interrupts: can be lost? Niklas Holsti <niklas.holsti@tidorum.invalid> - 2020-07-08 11:43 +0300
      Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 12:24 +0200
        Re: Interrupts: can be lost? antispam@math.uni.wroc.pl - 2020-07-09 23:24 +0000
          Re: Interrupts: can be lost? Dave Nadler <drn@nadler.com> - 2020-07-09 17:13 -0700
          Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-10 08:09 +0200
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 23:39 -0700
            Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 08:59 +0200
      Re: Interrupts: can be lost? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-08 14:57 +0300
        Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 07:01 -0700
          Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-08 16:07 +0200
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 07:35 -0700
              Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-09 14:16 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 11:04 -0700
                Re: Interrupts: can be lost? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2020-07-09 14:32 -0400
                Re: Interrupts: can be lost? Paul Rubin <no.email@nospam.invalid> - 2020-07-09 11:47 -0700
                Re: Interrupts: can be lost? lasselangwadtchristensen@gmail.com - 2020-07-09 15:22 -0700
                Re: Interrupts: can be lost? Dave Nadler <drn@nadler.com> - 2020-07-09 15:35 -0700
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 18:41 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-10 16:01 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 23:28 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-29 19:44 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 13:23 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-29 22:57 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 16:47 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 10:04 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 17:46 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 11:04 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 21:16 -0700
                Re: Interrupts: can be lost? Clifford Heath <no.spam@please.net> - 2020-07-30 16:36 +1000
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-31 11:26 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-30 01:11 +0100
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-29 17:53 -0700
                Re: Interrupts: can be lost? Chris <xxx.syseng.yyy@gfsys.co.uk> - 2020-07-30 19:05 +0100
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-31 00:21 +0300
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-08-04 20:40 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-08-04 14:36 -0700
                Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-08-04 22:32 -0400
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-08-05 15:26 +0200
                Re: Interrupts: can be lost? upsidedown@downunder.com - 2020-07-30 08:31 +0300
                Re: Interrupts: can be lost? Tom Gardner <spamjunk@blueyonder.co.uk> - 2020-07-30 07:53 +0100
                Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-07-30 08:10 -0400
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-09 18:40 -0700
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 09:09 +0200
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-10 01:41 -0700
                Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-10 13:47 +0200
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-11 13:41 +0300
          Re: Interrupts: can be lost? Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2020-07-08 17:33 +0300
            Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-08 09:31 -0700
              Re: Interrupts: can be lost? David Brown <david.brown@hesbynett.no> - 2020-07-09 14:30 +0200
              Re: Interrupts: can be lost? Przemek Klosowski <przemek@tux.dot.org> - 2020-07-19 18:38 +0000
                Re: Interrupts: can be lost? Dimiter_Popoff <dp@tgi-sci.com> - 2020-07-19 23:11 +0300
                Re: Interrupts: can be lost? Rick C <gnuarm.deletethisbit@gmail.com> - 2020-07-19 13:43 -0700
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-08 13:19 +0200
  Re: Interrupts: can be lost? Richard Damon <Richard@Damon-Family.org> - 2020-07-09 08:00 -0400
  Re: Interrupts: can be lost? dalai lamah <antonio12358@hotmail.com> - 2020-07-11 12:12 +0200
    Re: Interrupts: can be lost? pozz <pozzugno@gmail.com> - 2020-07-13 08:35 +0200

csiph-web