Re: Re: RS485 - XPL on the wire

["Frank Mc Alinden" <fmcalind@xxxxxxxxxxxxxx>]

Ian
Canbus might be a better option than rs485 as the canbus chips take care
collisions etc and no master is required..???....Dave McLaughlin uses
canbus
in his setup....
Frank

----- Original Message -----
From: "Frank Mc Alinden" <fmcalind@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Friday, October 22, 2004 7:11 PM
Subject: Re: [ukha_xpl] Re: RS485 - XPL on the wire


>
> Hi Ian
>
> > One station can talk, the others listen - easy enough, but how
can you
> > *tell* someone else is talking?
>
> AFAIK  you cant ......each node only responds to an Addressed message
from
a
> Master .....so thererfore not interested in whos talking ....or are
you
> interested in whos talking ????
>
> Frank
>
>
> ----- Original Message -----
> From: "Ian Lowe" <ian@xxxxxxx>
> To: <ukha_xpl@xxxxxxx>
> Sent: Friday, October 22, 2004 7:05 PM
> Subject: RE: [ukha_xpl] Re: RS485 - XPL on the wire
>
>
> >
> > One of the biggest gotcha's for me was simply the technical
aspects of
> > RS485 on the wire...
> >
> > One station can talk, the others listen - easy enough, but how
can you
> > *tell* someone else is talking?
> > I guess I'm thinking in terms of a CSMA/CD situation like
ethernet and
> > couldn't find any RS485 chip that gave you Carrier feedback to
indicate
> > that the media was in use.
> >
> > I guess you'd have to implement a token passing network system
like
> > token ring...
> >
> > Ian.
> >
> > -----Original Message-----
> > From: Frank Mc Alinden [mailto:fmcalind@xxxxxxx]
> > Sent: 22 October 2004 08:07
> > To: ukha_xpl@xxxxxxx
> > Subject: Re: [ukha_xpl] Re: RS485 - XPL on the wire
> >
> >
> > Hi Lehane / Ian
> >
> >             Like Ian  I am also interested in xpl 485 enabling
> > stuff...But to develope stuff we need to get more feedback from
xPL
> > Users on the sort of devices that they would like....Would be
nice if
> > several rs485 developements going on at the same time by
different
> > people.....I think there would need to be a RS232 / 485 convertor
made
> > which means one side would have to be bit banged , not aware of
any pics
> > with  2 uarts ??or a commercially available unit ??
.............Have
> > done a little bit on rs485 and used the chksum as you
> > decribed.............Im more than happy to get involved in
> > rs485 projects if  others are and there is enough interest as
well......
> >
> > This link mentions the rs485 stuuf i was playing with
> > http://skybax.rapidhoster.co.uk/~armagh/page10.html
> >
> > Frank
> >
> >
> > ----- Original Message -----
> > From: "g8kmh" <lehane@xxxxxxx>
> > To: <ukha_xpl@xxxxxxx>
> > Sent: Friday, October 22, 2004 1:49 AM
> > Subject: [ukha_xpl] Re: RS485 - XPL on the wire
> >
> >
> > >
> > >
> > > OK,
> > > I'd missed xpl_devcom in my searches, oops!
> > >
> > > LRC-8 is a simple checksum on the message. XOR everything
after STX
> > > including ETX and the result is the checksum. No big deal to
do and
> > > offers some protection against message corruption, which
since the
> > > RS485 is going to be around mains cabling (even taking into
account
> > > normal separations) I think is a reasonable precaution.
> > >
> > > Be interested in the PIC implementations....
> > >
> > > Thanks,
> > > Lehane
> > >
> > > <snipped>
> > >
> > >
> > >
> > >
> > >
> > >
> > > xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> > http://www.xpl.myby.co.uk
> > > To Post a Message: ukha_xpl@xxxxxxx
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> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> >
> >
> > xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> > http://www.xpl.myby.co.uk
> > To Post a Message: ukha_xpl@xxxxxxx
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> >
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> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
> http://www.xpl.myby.co.uk
> > To Post a Message: ukha_xpl@xxxxxxx
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> >
> >
> >
> >
> >
>
>
>
>
> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
http://www.xpl.myby.co.uk
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