Hello:

I don't know if my original email got out, but I am looking
for any verilog implementation of the DMX512 protocol, which
is used to control light dimmers. It is a serial protocol
that sends packets of 512 bytes down a single serial line.

Any pointers would be appreicated.

Thank you

Mark Allyn

Hi Mark, Both messages were received, lack of response probably indicates that no one is currently working on it. Out of curiosity, though, did you mean 512 *bits*? 512 bytes seems excessive for turning on and off a light switch... - Guy On 5/23/06, Mark Allyn allyn at well.com> wrote: -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums.cgi/cores/attachments/20060524/a7488a33/attachment.htm

Doing some goolgle, looks like it is (upto) 512 bytes... Just blasts to all devices at once... repeatedly... And it's basically 250,000 bps using RS-485. (Using http://www.pangolin.com/LD2000/dmx-about.htm as reference). So if you combine a 8 bit soft cpu (or some other logic) device with a RS-485 driver... ________________________________ From: cores-bounces at opencores.org [mailto:cores-bounces at opencores.org] On Behalf Of Guy Hutchison Sent: Wednesday, May 24, 2006 12:24 PM To: Discussion list about free open source IP cores Subject: Re: [oc] Looking for Varilog implementation of DMX (resend) Hi Mark, Both messages were received, lack of response probably indicates that no one is currently working on it. Out of curiosity, though, did you mean 512 *bits*? 512 bytes seems excessive for turning on and off a light switch... - Guy On 5/23/06, Mark Allyn allyn at well.com> wrote: Hello: I don't know if my original email got out, but I am looking for any verilog implementation of the DMX512 protocol, which is used to control light dimmers. It is a serial protocol that sends packets of 512 bytes down a single serial line. Any pointers would be appreicated. Thank you Mark Allyn _______________________________________________ http://www.opencores.org/mailman/listinfo/cores -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums.cgi/cores/attachments/20060524/e63f17b6/attachment.htm

Not sure what the RS-485 line protocol is, but since it's usually cross-listed with RS-232 and RS-422, it looks like it might be the same serial UART with a differential driver. In which case, it would be simple to use (for example) the TV80 with its included 16450 UART and hook it up to an external diff driver. And yes, it looks like a pretty simple protocol. In fact, for the device side, a micro might be overkill. Reading between the lines, it looks like it sends out a "start" character, then blasts out a series of light #/level pairs. Each light just looks for its own light number. If you miss it, no big deal, it will resend shortly... On 5/24/06, Lauro, John jlauro at umflint.edu> wrote: -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums.cgi/cores/attachments/20060524/6f729648/attachment.htm

Apparently I gave DMX credit for more complexity than it has. Wikipedia has a pretty detailed article on DMX: http://en.wikipedia.org/wiki/DMX_%28lighting%29 - Guy -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.opencores.org/forums.cgi/cores/attachments/20060524/567fb077/attachment.htm