You can set motion board UC300 at 25-50-100-200-400 Hz and I have seen a connection with something with the frequency setting it at the engraving. 400 HZ, the dac loses its position at once. I'll research more about why it is so.
I have tried to run the UC300 with dac but it was worse than mach3.
I took out the pwm signal to the laser driver from the UC300 port 3 and pin 3.
Run M10 Qxx g code from picengrave 3D laser starts M3 and it engraves but gets strange results.