Re: Re: RS485 - XPL on the wire

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

Hi Mal
Just had a look at that Guys ASM code I  assumed that a uart
would be needed for the dmx output....He just bit bangs it out.....

It looks like it could be done easily using a 16f876....my only concern
would be processing the incoming xpl message which in my setup is interrupt
driven...and can only process info after all channels has been updated....I
think it would also fit into a 16f88 (4k?) .....

When you say that dmx units are a lot cheaper than cbus dimmers how much
are
they ???

Would people purchase Dmx units for their lighting control ???

If i can pick one up cheap i would have a go at xpLling it........

Also does dmx have an  All channels ON / OFF  command ??? if not would some
channel numbers have to be reserved for these functions

Below is what i would assume to be an xPL Dmx command..???looks ok ???

*********
xpl-cmnd
{
hop=1
source= xpl-xplhal.mainpc
target=aec-dmx.mainpc
}
dmx.basic
{
channel=20
level=45
}

****************************************************

Frank



----- Original Message -----
From: "Mal Lansell" <mlansell@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Sunday, October 24, 2004 2:59 AM
Subject: [ukha_xpl] Re: RS485 - XPL on the wire


>
>
> --- In ukha_xpl@xxxxxxx, "Frank Mc Alinden"
<fmcalind@b...>
> wrote:
>
> >
> > So each node must have its light level refreshed every so
> often...Sounds
> > like the dmx stuff would require its own  rs485 network ..????
> >
> > Just had a browse and read some dmx512 stuff.......My thoughts on
> an xPL
> > Hardware interface would be as follows...
> >
> > Have a device which has two pics , One to listen to the xPL
Network
> > connected via rs232.. and the other to Transmit the dmx data and
> keep track
> > of the dimmer channel levels......Connect an 8 bit port between
> each device
> > and have a couple of control lines ie a data / node line to tell
> the dmx pic
> > that the info on the 8 bit port is either data (light level) or
> channel
> > number ...So two bytes would be transferred  between the pics
with
> every
> > xPL-DMX command received ...........
> >
> > Frank
> >
>
> Why two PICs?  This guy has built a 64 channel DMX interface with a
> single 16F84 hanging off the parallel port.
> http://users.skynet.be/kristofnys/
>
> I would have thought a more powerful PIC could deal with both the
> small amount of serial port traffic from the PC and sending the DMX
> data.
>
> Mal
>
>
>
>
>
>
>
>
> xPL Links: http://www.xplproject.org.uk http://www.xplhal.com
http://www.xpl.myby.co.uk
> To Post a Message: ukha_xpl@xxxxxxx
> To Subscribe:  ukha_xpl-subscribe@xxxxxxx
> To Unsubscribe:  ukha_xpl-unsubscribe@xxxxxxx
> Yahoo! Groups Links
>
>
>
>
>
>
>