Re: RS485 - XPL on the wire

["Mal Lansell" <mlansell@xxxxxxxxxxxxxx>]

--- 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