Well, now don't get me wrong. You _can_ use Windo(ws/ze) in a real time
environment. You just have to define your real-time requirements reasonably,
with an acceptable fallback when the timing isn't met.

For example, in the current case where we have to turn around and RS485 line
to pick up the reception the cost of a real-time failure will most likely be
a retransmit (and a collision on the RS485 bus). If that is acceptable (in
fact when N consecutive retries are acceptable) then you could use
Windo(ws/ze) in this environment.

You just have to know your limitations and consequences.

Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

----- Original Message -----
From: M. Adam Davis <adavis@UBASICS.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, August 21, 2000 11:32 AM
Subject: Re: [PIC]: Commx with half duplex RS485


> You are correct, of course.  You shouldn't be using a non-realtime OS
(windows,
> in this case) to control a realtime system.
>
> Ideally you would use a realtime controller to go between the windows
computer
> and the network to handle those issues.  ie, a realtime <---> non-realtime
> interface.
>
> -Adam
>
> Bob Ammerman wrote:
> >
> > Your turn around delay is 1 character, plus whatever delays are
introduced
> > by the most-certainly-nowhere-like-realtime Windoze before dispatching
your
> > program.
> >
> > Bob Ammerman
> > RAm Systems
> > (contract development of high performance, high function, low-level
> > software)
> >
> > ----- Original Message -----
> > From: Alan B. Pearce <A.B.Pearce@RL.AC.UK>
> > To: <PICLIST@MITVMA.MIT.EDU>
> > Sent: Monday, August 21, 2000 9:28 AM
> > Subject: Re: [PIC]: Commx with half duplex RS485
> >
> > > >Yeah, but you still have to turn off your transmitter when you
receive.
> > > >That's the whole point off the 2-wire half-duplex link.
> > >
> > > but after you receive the last character you know you transmitted, you
> > know you
> > > can turn off the transmitter. It gives you a one character turn around
> > delay
> > > maybe. It saves having to know when to turn on the receiver
> > >
> > > --
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> >
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