AVR-Chat

You could offset the 2.5V to favor the green LED; however
I have found that most red/green modules have very poor
response in the green LED, no matter what you do.  If you
have the space, you could put two separate LEDs back-to-back.
Although you might like to use a truer green color, you are
probably stuck with the awful yellowish-green because of the
lower forward voltage.
Ken

> Roy wrote:
>> See attached WORD file of the Switcher CAD III plot of the circuit
>> below.
>
> Thanks Roy for the analysis info.
>
>> *From:*  *Russell Shaw
>
> Thanks Russell for the original circuit.
>
> One problem of course is getting enough current to drive the LEDs to a
> reasonable brightness. This is mostly due to having them run from what
> is effectively a 2.5 Volt rail. Differences in brightness between red
> and green LEDs because of different operating voltages is also
> exacerbated.
>
> I'm leaning towards using a shift register like the 74HC595 and
> sending it data via the SPI - in my current design this allows me to
> control up to 8 LEDs with just the original extra pin!  And it takes
> about the same PCB real estate too.
>
> Peter
>
>
>
>
>
>
> .
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>