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Groups > comp.arch.embedded > #29768

Re: Interrupts: can be lost?

From pozz <pozzugno@gmail.com>
Newsgroups comp.arch.embedded
Subject Re: Interrupts: can be lost?
Date 2020-07-08 08:16 +0200
Organization A noiseless patient Spider
Message-ID <re3obo$fmg$2@dont-email.me> (permalink)
References <re2thr$ke8$3@dont-email.me> <a291b83d-1e6f-4bb9-b1b7-2d111feb7a0bo@googlegroups.com>

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Il 08/07/2020 01:14, Rick C ha scritto:
> On Tuesday, July 7, 2020 at 6:38:55 PM UTC-4, pozz wrote:
>> 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 believe that statement is not adequately supported in the document.  The best support I found in this document were the words, "As a result, the response to the second interrupt willbe at the very least delayed; under some circumstances it will be ignored altogether." which were repeated for three different conditions of mixed interrupt usage in the 8051 processor.  Maybe these are true statements for that processor under those conditions.  But that is not a blanket statement about interrupt usage.  Unless there is a flaw in the hardware or a flaw in the software, interrupts should not be missed.
> 
> A flaw in software or hardware can make any portion of a processor system fail.  Recall the infamous floating point bug in the Intel processors of a couple decades ago.
> 
> I also don't see any supporting information in your claims of interrupt failures being "practically impossible" to prevent.

That is not may claim, I only cited a sentence of a book I'm reading.


> If you are basing your claim on this article, I don't see your claim as being valid.
> 
> I will acknowledge that many times it can be hard to design interrupt based systems that work correctly.  That doesn't mean "impossible" or even "unlikely".  It means you have to give it due diligence.  This is the nature of using a sequentially executing processor to emulate simultaneous execution of processes.
>   
> I will also say that is why I design FPGAs in HDL.  The problems of multiple interrupt levels just don't happen in hardware.  Why make problems that are harder to solve than the problem you are trying to solve?

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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

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