You enable the driver for row 0, and PWM the 6 LEDs in that row with the 6 column driver. Then you enable the driver for row 1, and PWM the 6 LEDs in that row with the 6 column driver. etc. In other words, just like a normal 6x10 multiplex, except that you don't give each LED a full width pulse during what would normally be its 'on' time. To be more concrete: turn on columns 1 and 3 enable row 0 wait a bit turn off column 1 wait until next row time disable row 0 turn off all columns turn on column 2 enable row 1 wait a shorter bit turn off column 2 wait until next tow time disable row 1 turn off all columns ... In this case, the LED at row 0, column 3 would be full brightness, row 0 column 1 would be dimmer, and row 1 column 2 would be dimmer still. Bob Ammerman RAm Systems ----- Original Message ----- From: "Shahid Sheikh" To: Sent: Tuesday, December 16, 2003 12:22 AM Subject: Re: [EE:] Driving multiple RGB LED's...? >>Hmmm... And with a 2-dimensional PWM control you might be able to >>control the brightness of each LED color too. Won't be able to use a >>decade decoder. Will have to address each of the 10 rows directly. >This is not true. You do your modulation with the 6 column drivers. But wouldn't that mean all the LEDs in one column would have the same brightness? Or am I missing something here? Shahid -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body