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Groups > comp.arch.embedded > #25791
| From | Don Y <blockedofcourse@foo.invalid> |
|---|---|
| Newsgroups | comp.arch.embedded |
| Subject | Re: Do you use FSMs or HSMs? |
| Date | 2017-02-06 21:50 -0700 |
| Organization | A noiseless patient Spider |
| Message-ID | <o7bjk1$rfu$1@dont-email.me> (permalink) |
| References | <o79gce$om1$1@dont-email.me> <87k292ybhk.fsf@nightsong.com> |
On 2/6/2017 7:35 PM, Paul Rubin wrote:
> pozz <pozzugno@gmail.com> writes:
>> My post here is to understand if you really use HSMs to describe the
>> beahviour of the system you are coding and how do you implement them
>> in C or C++ (or whatever).
>
> I looked up HSM in Wikipedia and see it's UML-speak for nested state
> machines. I don't see exactly how it applies to the calculator example
> but I've preferred to use multiple communicating processes with the
> appearance blocking operations, rather than explicit state machines. Of
> course you can simulate that with an event dispatcher and coroutines, or
> alternatively do it with an RTOS and tasks. I suppose there is overhead
> compared to a FSM or HSM approach, but on the big processors I use, it
> hasn't been an issue.
IME its not the space/time efficiency but, rather, the conciseness of
expression.
Designing/debugging an algorithm ("machine") with a state diagram is
*so* much easier to sort out what is happening -- and what ISN'T,
that should!
There are tools that can take diagramatic representations and
convert them to code. But, they make assumptions about the
implementation that constrain your solution space. Using the
design concept without committing to a particular implementation
style is where the biggest wins lie.
[And, there are "mechanical" ways that you can reduce the complexity
of state machines once you've settled on one that works]
However, just approaching the problem in a way that lends itself
to this sort of visualization makes a huge difference vs. trying to
trace paths through code (in potentially different process containers
or on different physical processors).
It also lends itself to having others (Manglement) review the
(planned) behavior without requiring them to understand the
latest implementation language, modeling language, etc.:
"What if a power fail event is signalled while I'm OVER HERE?
How is it handled if the user stalls his interaction at this
point -- which doesn't RECOGNIZE the event until after he has
done X, Y or Z?"
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Do you use FSMs or HSMs? pozz <pozzugno@gmail.com> - 2017-02-06 10:43 +0100
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 03:20 -0700
Re: Do you use FSMs or HSMs? Dave Nadler <drn@nadler.com> - 2017-02-06 06:38 -0800
Re: Do you use FSMs or HSMs? "QL" <80499@EmbeddedRelated> - 2017-02-06 08:56 -0600
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 12:13 -0700
Re: Do you use FSMs or HSMs? jim.brakefield@ieee.org - 2017-02-06 16:52 -0800
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 18:11 -0700
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-06 23:32 -0600
Re: Do you use FSMs or HSMs? pozz <pozzugno@gmail.com> - 2017-02-07 10:39 +0100
Re: Do you use FSMs or HSMs? John Speth <johnspeth@yahoo.com> - 2017-02-06 09:17 -0800
Re: Do you use FSMs or HSMs? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-06 18:03 +0000
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 11:56 -0700
Re: Do you use FSMs or HSMs? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-06 20:34 +0000
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 14:19 -0700
Re: Do you use FSMs or HSMs? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-06 22:12 +0000
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:29 -0700
Re: Do you use FSMs or HSMs? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 12:15 -0500
Re: Do you use FSMs or HSMs? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-08 23:52 +0000
Re: Do you use FSMs or HSMs? Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> - 2017-02-08 19:59 -0500
Re: Do you use FSMs or HSMs? Steve Watt <steve.removethis@Watt.COM> - 2017-02-17 00:30 +0000
Re: Do you use FSMs or HSMs? Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-02-17 00:44 +0000
Re: Do you use FSMs or HSMs? Clifford Heath <no.spam@please.net> - 2017-02-07 10:12 +1100
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-06 23:36 -0600
Re: Do you use FSMs or HSMs? George Neuner <gneuner2@comcast.net> - 2017-02-07 03:15 -0500
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-10 17:41 -0600
Re: Do you use FSMs or HSMs? Clifford Heath <no.spam@please.net> - 2017-02-07 19:56 +1100
Re: Do you use FSMs or HSMs? Paul Rubin <no.email@nospam.invalid> - 2017-02-07 01:30 -0800
Re: Do you use FSMs or HSMs? Clifford Heath <no.spam@please.net> - 2017-02-07 20:42 +1100
Re: Do you use FSMs or HSMs? Paul Rubin <no.email@nospam.invalid> - 2017-02-07 02:46 -0800
Re: Do you use FSMs or HSMs? Clifford Heath <no.spam@please.net> - 2017-02-08 00:27 +1100
Re: Do you use FSMs or HSMs? Paul Rubin <no.email@nospam.invalid> - 2017-02-06 18:35 -0800
Re: Do you use FSMs or HSMs? Don Y <blockedofcourse@foo.invalid> - 2017-02-06 21:50 -0700
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-06 23:39 -0600
Re: Do you use FSMs or HSMs? Paul Rubin <no.email@nospam.invalid> - 2017-02-06 23:20 -0800
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-10 17:47 -0600
Re: Do you use FSMs or HSMs? Paul Rubin <no.email@nospam.invalid> - 2017-02-10 16:11 -0800
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-11 15:43 -0600
Re: Do you use FSMs or HSMs? Les Cargill <lcargill99@comcast.com> - 2017-02-06 23:24 -0600
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