On Sun, Apr 18, 2004 at 08:26:08AM -0400, Chris Oesterling wrote:
> All,
> I'm hoping to find a simpler solution to what I thought would be a
> simple task of driving a single green/red bicolor LED from a PIC.

It is a simple task.

> Reversing polarity isn't easy!

Sure it is! You just have to be able to control both legs of the LED.

>  I have found an old article that uses a
> relay

Yuck!

> or suggests a better solution of using a couple of transistors and
> resistors.

Not much better. It really requires some parts and work to get it going.

>  Sorry for such a basic question.

Not basic at all. Fortunately the PIC can help you.

>  I searched the archives and only found a matrix solution.

Simple solution: 2 I/O pins each tied to a leg, with a current limiting
resistor between one pin and a leg. Then you can control the LED simply
by having opposite values on the the pins. So a 0 on pin A and a 1 on pin B
will light the LED with one color, while a 1 on pin A and a 0 on pin B will
light it the other. If the pins are the same value, the LED is off. If you
oscillate the pins, you get the blended yellow/orange color.

BAJ

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