At 02:37 PM 4/15/01 -0700, you wrote:
>Here is what I suggest:
>
>use  8 output pins
>one input pin
>pull down the input with a 10k resistor
>every output pin is connected to the input pin
>thru a switch
>the switchs also have an led and resistor
>connected to ground on the side opposite from
>the output
>
>using 1/8 duty cycle,
>set each output pin in turn to 5v
>at this time also set the other outputs to inputs
> if someone presses a switch, 5v is detected
>at the input, so the code should pause until the 5v is gone.
>the led will light on the switch press.

You can use one more output to keep the lights from
all lighting while it is scanning (keep it high (or open)
until a hit is detected- it goes to the LED common).

Also, when the first press is detected multiple leds may
show until some of the switches are released. You'd need
diodes on each switch to get around that. I'd suggest an
18-pin PIC16F627 with internal 4MHz clock for minimum parts
count.

Best regards,
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