Re: Re: RS485 - XPL on the wire

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

Hi Mal

> The dmx interface hardware would only have to deal with those two byte
> channel/level commands - not a full xPL message.  There would be a PC
> service handling the xPL side of things in the same way that the CM12
> service does for X10.

I got the impression that it was always best for a piece of hardware to
talk
native xPL ...???

Im not sure how much processing the xPL message in software  is required
,but if i make it talk native xPL then all thats  required is to use Tonys
devcom....???

> The heaviest load would be on the DMX side, where the data has to be
> continually pumped out - this might be the best side to use the UART,
> with the PC side (RS232?) handled through bit-banging.

Yes that may be the way to go.....Having read a bit on the specs it looks
like its possible to capture data during the Break period and also  the
Inter frame period .........


> To produce the equivalent of all channels off, you would have your
> DMX interface just send a stream of zeros (and yes, you would need to
> reserve a channel for special commands from the PC).

Thats what i suspected ............

> As for dimmer packs - they are often available on Ebay.  Otherwise,
> it looks like you can get 4 channels for around 100 pounds (e.g. the
> Chauvet DMX35 dimmer).

Might have to try ebay.................


> Of course, it's not just lights that are DMX enabled - you could turn
> your house into a virtual nightclub!

Dont think the wife would like that ;-)..Although im sure my teenage boys
would like it........

So would you be interested in an  xPL-DMX Interface ??????

Frank


----- Original Message -----
From: "Mal Lansell" <mlansell@xxxxxxx>
To: <ukha_xpl@xxxxxxx>
Sent: Monday, October 25, 2004 12:15 AM
Subject: [ukha_xpl] Re: RS485 - XPL on the wire


>
>
> The dmx interface hardware would only have to deal with those two byte
> channel/level commands - not a full xPL message.  There would be a PC
> service handling the xPL side of things in the same way that the CM12
> service does for X10.
>
> The heaviest load would be on the DMX side, where the data has to be
> continually pumped out - this might be the best side to use the UART,
> with the PC side (RS232?) handled through bit-banging.
>
> IIRC, there's no all channels on/off command - the system consists
> only of a stream of light level bytes.  Each DMX-controlled device
> has to count the bytes until it gets to the one meant for itself, and
> then uses that byte to set its own light level.  The count resets
> when there is a pause (I forget how long) between bytes.
>
> To produce the equivalent of all channels off, you would have your
> DMX interface just send a stream of zeros (and yes, you would need to
> reserve a channel for special commands from the PC).
>
> As for dimmer packs - they are often available on Ebay.  Otherwise,
> it looks like you can get 4 channels for around 100 pounds (e.g. the
> Chauvet DMX35 dimmer).
>
> If you want to DIY the whole thing, there is also a company making
> DMX controlled dimmer chips (basically a pre-programmed PIC) that
> handle all the timing for dimming via solid state relays.
> www.artisticlicence.com
>
> Of course, it's not just lights that are DMX enabled - you could turn
> your house into a virtual nightclub!
>
> Mal
>
>
>
>
>
>
> --- In ukha_xpl@xxxxxxx, "Frank Mc Alinden"
<fmcalind@b...>
> wrote:
> > 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
> >
>
>
>
>
>
>
>
>
>
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