Right on, Josh. The PICs work great when the LED's are solid (not
multiplexed) but when multiplexing is needed, there is usually not
enough current.

The 74HC595 is hefty BUS-driver part, and can pump a lot of current into
a multiplexed display. I used it for both the HIGH side AND the LOW
side. Only current limiting resistor needed.

--Bob

Josh Koffman wrote:

> The options presented so far are all rather good. I know that using the
> same pins for different things can be a bit intimidating, so allow me to
> offer another idea. Serial shift registers. You could use a serial to
> parallel to light your displays, then a parallel to serial to read your
> switches. More components and thus a higher cost, however you are less
> dependent on time.
>
> Josh
> --
> A common mistake that people make when trying to design something
> completely foolproof is to underestimate the ingenuity of complete
> fools.
>         -Douglas Adams
>
> Vlad wrote:
>
>>I'm in the process of designing a toy circuit to keep track of life
>>counters for various games.  It should support 3 players.  Each player
>>will have two 7 segment LED displays that will display a number between
>>0-99, and also 2 switch buttons that will be used to increase and
>>decrease the number displayed on these LED displays.
>


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                Bob Axtell
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