Patrick -

By useing something like a 74138 Decoder you would only have to
use 3 outputs to control the common grounds of your digits, this
would save you 5 i/o pins. You could also use a shift register
to get down to about 2 pins to control your outputs.

Of course, if you don't need the extra i/o, then it doesn't matter.

Mike Gann

Patrick Lamontagne wrote:
>
> I'm just writing to tell you I finally figured out how you suggested
> to multiplex digits. I have 8 outputs that are connected to the
> 8 segments (7 segments + 1 dot) of all the digits at the same
> time. and the common ground of each digit is controlled by
> 8 other outputs. That makes 16 outputs for 8 digits !
>