Hope you find the problem.
If not there is more hardware debugging you could do with just a voltmeter/DMM and a simple test program
I am just thinking that nearly all LED-pars have also a standalone mode.
Anyway i don't see much more that you could have done wrong. The little details about the terminators (and even the 4.5v power supply) tend not to cause issues in Lab testing circumstances where only short cables are used (with twisted pairs or not. Twisted pairs are not optional outside of the LAB ! )
On an AVR i have always used Conceptinetics, and i knwo that works. I know DmxSimple works although it uses more than half of the processor to do so.
I am trying to remember how i managed the first step, since i started out building a receiver. It's such a long time ago.
Good news! It turned out the fixture was bad, it looks like my hardware is good.
I'll double check soon, but for now I have a good feeling about this.
Thanks for all your help so far.
Good luck
Have a nice day
It works! at least the dmx part, now I have to add the other hardware.
luckily I had that working before, so that shouldn't be a problem.
Thanks again for all the help, I'll mark this thread as solved.
Hurray!
may I ask what was the final code you used etc? I am trying to make a really simple sketch to do anything through a dmx shield and the light wont go on.