Re: Do you use FSMs or HSMs?

From	Don Y <blockedofcourse@foo.invalid>
Newsgroups	comp.arch.embedded
Subject	Re: Do you use FSMs or HSMs?
Date	2017-02-06 12:13 -0700
Organization	A noiseless patient Spider
Message-ID	<o7ahp2$mg1$1@dont-email.me> (permalink)
References	<o79gce$om1$1@dont-email.me> <AdednQRvfaY4EwXFnZ2dnUU7-d_NnZ2d@giganews.com>

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On 2/6/2017 7:56 AM, QL wrote:
> So, yes, I also strongly believe that hierarchical state machines (a.k.a.
> UML statecharts) combined with event-driven programming are the best way
> to go when it comes to developing real-time embedded software.
>
> From my two decades of experience, however, I see that the biggest
> obstacle in adopting state machines is the required paradigm shift from
> sequential programming based on blocking (like blocking on a semaphore or
> a time delay in a traditional RTOS or a "superloop") and the event-driven
> programming based on run-to-completion event processing without blocking
> (like in a state machine).

The two aren't mutually exclusive.  So, silly to limit yourself to
that mindset.

And, a "machine" doesn't have to be a cohesive, monolithic block of
code easily recognizable as "something special".  It can, instead,
be coded "in-line" if the environment supports seemless redefinition
of program (task) entry points; the "current state" is then effectively
encoded in the "saved entry point" which is explicitly changed each time
you explicitly command it (yield()/reschedule())

In this way, you can undertake lengthy operations without resorting to
a preemptive MTOS/RTOS to ensure you aren't monopolizing the processor
as well as doing the same in a fully preemptive environment.

Thread

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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