What about power supply?

Why can't you multiplex smaller portion of the matrix.

For instance : 8 * 8 matrix multiplex.

When your controller has a high speed crystal input, you can improve your design.

make multiple boards containing those smaller boards and make a board enable bit for each unit.

This approch will remove all wories about serial clocking and latching.

OR

You can use a controller on each board that supports CAN.
Then send a CAN frame that sets the data on the board.

For eg. AT89C51CC02 Flash upgrade from CAN, etc ...

Multifunctional and ease of use !!


Bert Regards.

PS. : If you'd like to build your own SCROLLING MESSAGE BOARD ? Do not waste your money and Buy a standard messageboard.

It's a lot cheaper than building your own.

AND you have a designed case for free !!