Russell McMahon wrote: > The diodes are *necessary* if you wish to prevent phantom key action > and allow "N-key rollover". I agree. Using Tri-State will avoid Output-collisions, but to avoid phantom keys you'll need diodes (been there, done that :) -- Ciao, Dario -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist