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Groups > comp.arch.embedded > #29779
| From | David Brown <david.brown@hesbynett.no> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Interrupts: can be lost? |
| Date | 2020-07-08 16:07 +0200 |
| Organization | A noiseless patient Spider |
| Message-ID | <re4jun$jjr$1@dont-email.me> (permalink) |
| References | <re2thr$ke8$3@dont-email.me> <re3r2n$tme$1@dont-email.me> <hmlf8uFcbh7U1@mid.individual.net> <re4cbi$v3i$1@dont-email.me> <db827461-f75a-40de-b22c-15ad143c0abfo@googlegroups.com> |
On 08/07/2020 16:01, Rick C wrote: > On Wednesday, July 8, 2020 at 7:57:43 AM UTC-4, Tauno Voipio wrote: >> On 8.7.20 11.43, Niklas Holsti wrote: >>> On 2020-07-08 10:02, David Brown wrote: >>>> On 08/07/2020 00:38, 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. >>>> >>>> The book was written in 2001, using a microcontroller that, >>>> while very popular (and still not dead), was 20 years out of >>>> date at the time. I haven't looked at it yet, and can't judge >>>> the quality of the book. But beware that some things in it >>>> could be limited by that microcontroller architecture. >>>> >>>> However, the principle here is correct. It is part of a more >>>> general principle that is actually quite simple: >>>> >>>> If you have event counters or trackers that have limited >>>> capacity, and you do not handle the events before that capacity >>>> is exceeded, your system will lose events (by either ignoring >>>> new ones, or ejecting old ones). >>> >>> Indeed. >>> >>> Note that the book's author clearly has an axe to grind here[1], >>> because he advocates using "time triggering" instead of event- >>> (interrupt-) triggering. So he's trying to make you afraid of >>> interrupts. >>> >>> Of course a similar problem applies to time-triggered systems: if >>> you trigger a task every millisecond, but the task sometimes >>> needs more than a millisecond to complete... something bad can >>> happen. >>> >>> [1] Or, as is said here in Finland, "he has his own cow in the >>> ditch". >> >> >> The writer is advocating the 8051 family, which is awfully clumsy >> for running real multi-threading. Besides, it should be forgotten >> in favor of e.g. the Cortex-M processors, which are even at least >> as inexpensive as the 8051's with required support. >> >> (Mooo! from southern Finland). > > That would be nice in an ideal world. I know of one designer that > will still use the 8051 processor in designs that require a second > source and longevity of supply. When qualification of a design is > very expensive these properties can be very important. If the 8051 > is the only processor that meets these requirements then that is the > one you will use. Yes, but it is not the only option. > > There are many, many ARM MCUs on the market today. Which ones will > still be around in 20 years? > The ones that manufacturers say they will continue to produce. Any manufacturer with automotive customers will have long-term guarantees. (I don't know how common 20 year lifetimes are - I haven't had to look /that/ long.) Second sources are not easy if you need /exact/ matches, but your friendly local distributors can help.
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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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