My need is to drive an RGB LED which is more or less like driving 3
discreet LEDs.  Since I want to be able to generate an arbitrary
color and brightness, and still have lots of PIC left to do other
things, using a part with 3 hardware PWM outputs seemed like a
natural.

The problem is my work is somewhat constrained (my skills and tools
are at the level of clever (I hope!) hobbyist rather than working
engineer) and it looks like there isn't a part I can work with this
way:

* there are some PIC17xxxx's that have 3 PWMs, but they are not
flash-able...a development problem for me, plus I want the final
product to be field programmable.

* the PIC18F458 and PIC18F448 are DIPs and claim 5 PWMs but my
reading is that they are not fully independent units, but rather
produce related phases for motor control and thus not good for my
need to make arbitrary colors (right?)

* all the other PIC18xxxx's with 3 or more PWMs are in non-DIP
packages like TQFP and so too difficult for me to work with.  (Tried
to find some socket converters...at $50 and more they are as much or
more than my total per-unit parts budget!).

Alternatives I've thought of:

* use 2 PICs which each have 2 PWMs and have them talk to each other
when it's time to change colors

* bit bang 3 pins for independent PWM...but if I do that with enough
resolution (8 bits minimum...10 better) I think I will run out of
cycles...

* ...but if I can almost get that working I could make a dedicated
RGB driver chip with one PIC, and then program a main PIC to do all
the other work and  tell the RGB driver chip what
hue/saturation/brightness it wants with a 3 byte message.

* ...but then I might as well investigate other off-chip DACs...

MY QUESTIONS - any new PICs coming soon that offer 3 or more
independent PWMs in an easy to use DIP package?  Any other
alternatives I've not thought of?

thanks, Phil

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