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Old December 10th, 2013   #11
dtewksbury
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Join Date: Nov 2011
Location: Phuket, Thailand
Posts: 7
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Thank you all for the replies. It is always good to know what more experienced people are using for testing and their different quirks. I have always been disappointed by the stupidly large timing ranges of DMX, because it is not possible to analyze it to determine whether it is reversed or not. I have always wanted to design fixtures that would automatically invert the data line if necessary. I guess it was done this way originally because of hardware and processor limitations on simple implementations.

I have in no way implemented even the basic minimum required responses in my RDM implementation yet. I need to get the product working, with a nice software interface for demonstration, so I am using the manufacturer custom parameter ID 0x8000 and this GET/SET exchange does all the lighting parameters in one hit. I will do device discovery soon, so at least the fixtures can be found.

To be honest I have not quite wrapped my head around the discovery algorithm. What I mean is that I understand the concept, and in the PC it will be fairly straight forward to implement. But I am concerned about the micro's side of things. I need it to not be MCU intensive to do the comparisons, although I have found that 40MIPS is actually quite good at 25ns per instruction. But I am writing the micro code in C and I am not 100% sure how good the compiler is (ASM30/C30). I will find out when I put some set and clear pin statements at the beginning and end of some of the functions and then look at it on the DSO (yes, I am old enough to sometimes want to say CRO).

So far this has been quite a satisfying journey (frustrating at first).

Daryl.
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