Vlad said:
> 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.

6 displays and 6 switches? You can do it with almost no extra parts on a
16F84.

Use common cathode displays.

Use all of port A and one pin (RB7) from port B to drive 6 NPN
transistors, one for each digit, common emitter. With base resistors. RA4
will also need a pullup resistor.

The 7 segments are driven from the first 7 pins of port B through resistors.

Build that first and get it working.

Then add your switches to port B, on the segment side of the resistors.
The switches other side to ground.

Turn on "weak pullup on Port B".  Tristate RB0 through RB6. Make all of
port A and also RB7 low.

Read Port B for the switch status.

Done. Almost no parts.

Cheers,

Bob

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