if you create asm sub (you can see i.ex manolator source@4mhz) and call that sub every time when you want to make output, must be carefull, timings are critical read the dmx protocoll
another thing is dmx protocol is 250kb but is 11bit information with speciall startbit which is not standard. so forged using anny hserin or hseout exept if you can do some kind of hardware bit cutter/splitter-manipulator

sorry for my english, im not shure that i'm uderstundible

if someone is interested and able to programm DMX mini desk (i think can be done i.ex with 18f452) my wish is to see (and help)make those code (and schematic)