Re: Multiplex question for multiple RGB LEDs

On a sunny day (Thu, 03 Apr 2008 07:46:49 +0100) it happened Mike G
<no@xxxxxxx> wrote in <chc7v39c2v92jadrgsns8tn4qec9jinbee@xxxxxxx>:

I was proposing to use the following hardware method:
Tie all the Red cathodes to a MOSFET or NPN transistor, ditto Green &
Blue. Scan these at 300Hz (to get a 100Hz overall refresh) and drive
the 80 anodes from transistors using latched data from 74HC595s.

This has worked fine but trying to scan 3 columns requires an
interrupt at 76,500 Hz which is proving problematic. I have access to
AVRs or PICs.

Any advice appreciated.

Your hardware would be much simpler with an FPGA.
.