Hi.

Paralell loading of the LED drivers instead of the serial approach gives me umpteen time to do other tasks and yields to a bigger duty cycle deliverred to the columns, hence improving the LEDs intensity. In the 32x256 LED display, I multiplex each 32x32 matrix individually. Although I didn't see much flicker in my last displays refreshed @ ~50Hz for each column, I'd rather take your 100Hz scheme for granted. Assuming columns multiplexed @ 100Hz the frequency will be 32x100=3200Hz then I shall have some 1/3200=~312us time to do other tasks (fairly enough time to execute lots of instructions on a plain vanilla @ 11.0592MHz) though the need for Cygnal 50MHz 1 clocker is alleviated. Even there will be no need for the bitmap buffer (supposedly twice the display length) i.e. the refresh ISR launched every 312useconds or so can handle the task of reading from SRAM or FLASH and writing it directly to the latches per se. Moreover I needn't go through all that pain and overload to prepare appropriate serial data/clock/strobe to be fed to HC595, ST2221a or it's Deutch counterpart and this bullet-proofs my "gluteus maximus" against high freq. phnomena too.
Erik malund 11/Dec/01
These "ready made" panels might have applied some implications on you to go serial, you know...sometimes I do something, then look for "logical" reasons and surprisingly a handfull of robust reasons are often found! ;)just a say.

Best.