On 16 Sep 97 at 10:39, Martin R. Green wrote: > The other challenge with MUX'ing all segments separately is that you > would need 42 port pins, unless you used some kind of external S2P > chip (or several), which kind of defeats the "PIC direct drive" > theme of this thread. > Not what I meant. Common the segments, and connect one per PIC pin. Thats 8pins. Now connect the 4 cathodes from each display to its own pin. Thats 12 total. Software - Set all cathode IO pins low. Now tris them Set all segment IO pins hi and tris them. For the segment you want on, turn the 2 corresponding tris bits off (not trissed) - briefly... I'm a little tired, but I don't think this will reverse-bias any of the unused LEDS. 4 resistors, max, in the common cathode leads. MikeS (remove the you know what before replying)