in the 3 and 8 channel projects there are fixed dimmercurves from the forum named ...SKALIERT.c ,
( with the original calculation , dimming starts from ~35 % or dmx value 75 , this is also the point where voltage drops below 10v)
Since
(255-DMX_VAL)/2
will be max 128 or 127 and the dimmmer has 90 possible values from phase cutting , the transformation is done as suggested in his forum[1] via valMap
hint: the values are reversed 100%=0 ,0%=90 internal
-> atmel studio 7 -> new project -> c++ -> stk5000 (find com .. ) -> atmega328p -> insert sourceode -> build solution (f7) -> "tools→add target" -> "tools→device programming" -> "read"(top) ->memories (check for build to appear) -> erase flash -> program
[1] https://www.ulrichradig.de/forum/viewtopic.php?f=53&t=2656s