Looking for DMX512 schematics

[ShoKre]

i think not so eassy, (250kb11bit/specialstart-stop timing)....

give as some links if this is so easy....

I'm verry interested...

... googling you can find only asm stuf, with wery reserved explanation..
i think transmit is posible with asm-software sending routine combined with basic logic....

but for reciving, if someone know technics for capture (firstline bracket)
this shud be interesting post...

[RussMartin]

Thanks, Darrel!

I can handle RS485 with a Maxim product. I should have put the question differently.

Can someone point me to some generic software?

[DynamoBen]

If you do a search of this forum you will find some snips of code. Beyond that there is ASM code if you google. Keep in mind that there is more than one way to successfully decode DMX. Each method has its pros and cons. Make sure you have an in-depth understanding of the protocol before you begin.

[RussMartin]

Thanks, ShoKre. I already have an ENTTEC open USB interface for the transmit side, so I'm looking for ways to do the receiving.

[DynamoBen]

The forum has a few examples; one posted by me. I too am using the OpenDMX device for transmitting. Keep in mind that a "real" DMX transmitter transmits much quicker than the OpenDMX device (44Hz). I found that my code worked well when attached to the OpenDMX but didn’t work reliably on a standard lighting console. Have fun!

[RussMartin]

Holy smoke!

I assume you mean that your receiver didn't work on a standard console? How reliable/unreliable was it--total fiasco or just partial?

My ENTTEC (running under LightFactory, not the freeware stuff) runs the few DMX512 devices I've tried.

How did you arrive at the 44Hz (!) figure? Scope, specs, what? If it's truly that bad, I'm going to send the package back.

Can you give me a link to your code and/or schematic?

Thanks!

[DynamoBen]

I assume you mean that your receiver didn't work on a standard console? How reliable/unreliable was it--total fiasco or just partial?

My ENTTEC (running under LightFactory, not the freeware stuff) runs the few DMX512 devices I've tried.

My receiver worked fine at the slower speed of the ENTTEC (25-30Hz) but didn't run so well at full speed on a console (44Hz). I am trying to narrow down the bottle neck. The ENTTEC device runs DMX devices just fine, it’s an inexpensive way to produce DMX on a PC which is why I'm using it. That being said I still do final testing on a commercial lighting console.

How did you arrive at the 44Hz (!) figure? Scope, specs, what?

The DMX spec is where I get this number. With all the testing I've done the fastest the ENTTEC can transmit reliably is about 33Hz. Beyond that you start to see periodic errors. Visually you would never notice these errors I used a DMX tester to determine the highest refresh rate the ENTTEC could handle.

If it's truly that bad, I'm going to send the package back.

Not sure what you mean here.

Can you give me a link to your code and/or schematic?

The best resource is the search at the top of the page. There are a number of posts on this topic. In the search field type DMX* and you will get several hits. Beyond that learn and understand the protocol. Once you do all that it’s fairly easy to create the code.