Thank you all for your help! I always thought that controlling the LED panel is a piece of cake, but the more I investigate, the more complication it gets. Especially if I want to display animation or live video. Yes, there will be a case where all the LEDs have to be turned on. This is because I plan to add graphic to the display. The 16x16 module is just a small part of a bigger display panel. I also plan to add brightness control by adjusting the duty cycle. If I have to use a transistor for each output, there will be 32 of them per 16F877! I think an IC is more space-saving. Regards, Thomas Herbert Graf wrote: Well, it all depends, are there going to be cases where all of them are lit? A PIC output can drive one LED no problem, however the device also has a limit as to how much it can drive, and your 16x16 LEDs are certainly going to be more then a PIC could ouput. As for driver IC's, I don't see a need to use an IC when a jelly bean BJT will do the job. Again, it depends on exactly what you are doing (how are you multiplexing the display, etc.). TTYL -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads --------------------------------- Do you Yahoo!? The New Yahoo! Search - Faster. Easier. Bingo. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads