I have the hardware to test on.
I've already provided the schematic and the flow chart along my post
You'll have a problem with a small microprocessor if it also has to be a parallel output because you'll soon run out of GPIO pins.
Actually, that is fairly easy. That parallel output is what is fed to the DAC. When it is finalised, you merely strobe it to whatever successive device you wish.
most programmers are going to think of MSB as D7 and LSB as D0, and start loop counters at 0.