Joe.

It seems that you understand how the load and multiplex scheme works for the a single tile. If you built the MCU code to cycle the 5 columns of a single tile each LED would only be on about 20% of the time. When you propose to add 9 more of the 5x7 tiles it would not be advisable to extend the ring counter concept to 10 * 5 = 50 columns as then the LEDs would be only lighted for 2% of the time and they will be very dim. Instead you should consider the possibility to drive each additional tile with the same kind of logic as you showed in your schematic. You may be able to share the Ring Counter across five sets of the high side drivers but you should consider having a low side driver for each of the tiles.

If you follow this scheme you would spit out now ten sets of low side data for each time you clock the ring counter. With careful coding and design (keep the SPI shift rate fast) you should be able to keep the column clocking rate up fairly fast to reduce apparent flicker.

For the best LED visible performance you would look instead at providing a driver for every LED instead of using a MUX system but that of course increases your hardware cost quite a bit.

- mkaras