I have considred a 6 or 12 chan digital control PCB for the dimmers I designed 20 years ago but on carefull condieration have always come to the conclution that a singe 8051 or even 80C320 is probably too slow to both zservice the serial interrupt for the DMX data and the 25Khz timing to get 256 levels at 100Hz I anm currenty considering moving the timg to a FPGA chip