The Mx board below is indeed a multiplexing experiment. As the documentation of DM63x line of chips is pretty scarce, I have to find the right solution by trial and error.
The photo shows a 8×8 RGB matrix being run by a single DM633 (plus a couple of SN74HC138Ns). The photo may look cool, but in fact the image is flickering a bit. I’ve made another board with two DM633s, but it seems that the delay between the two chips turning on produces a very visible ghosting. In any case, I’ll do a more thorough report on DM63x multiplexing later, this is just a teaser of sorts.