> I'm sure we can drive a bi-colour led from one
> pic pin without having to resort to transistors.
> :o)

I have a feeling something like this could be made
to work, with some fiddling, to drive a bi-colour
led from one PIC pin. I don't know if it has any
real merits compared to the usual solutions.
At least it uses zero power in the "off" state
if it could be made to work.
-Roman


       +5v  ------------------------------------*------
                                                |
                   ?          1N4148            |
-----,     ,-------C---------*--|<----,         R 470 ohm
     |     |                 |        |         |
 PIC |     |                 '---R----*         |
     |     |                          |         |
     |     |     ,----|<---,          |         |
     |     |     |   Green |          |         |
     |-----*-----*         *----------*---------*
     |           |         |                    |
     |           '---->|---'                    |
     |                 Red                      |
     |           Bi-colour LED                  C 0.1uF
     |                                          |
-----'                                          |
                                                |
       Gnd  ------------------------------------*-----

            ,--------,  ,--------,  ,--------,
 Red on =   |        |  |        |  |        |
           -'        '--'        '--'        '--

 Green on =                                       (low)
           -------------------------------------

 Both off = ....................................  (high imp)

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