I had to change resistor R33 on the analog board to 0 ohms in order to make blanking work reasonably well, but it’s still not perfect. Your mileage may vary depending upon the exact scope that you connect to this interface. I’d like to move onto focussing on getting some real software working, but I have one more significant issue to resolve. I think that the loading of the latches off the data bus is a little flakey, which is causing some flickering of the display. I also have to investigate the artifact at the top of the screen a little more.
In case you are interested, here is the driver that was used to generate the display in the picture. Keep in mind that it is a very much a work in the progress.