Dennie Lee wrote:

> I need to make a small light bulb (like a grain of wheat type bulb)
> flicker randomly, similar to a candle.  I would prefer code that
> doesn't use hardware PWM (because I have a PIC16C84-10), but I will
> even go so far as to order a PIC just for this.

  You absolutely, certainly do not need PWM hardware for operating light
bulbs.  BTW, I don't think you need a PIC either.  The basic PRBNG to
perform this, clocked at 50 Hz, can be readily implemented with a 4024
and 4093 plus 2 resistors, capacitor and one driver transistor.

  Of course, you can do it with a SMD 12C509 but you still need the
driver transistor.  I suppose you might possibly get away with four or
more outputs in parallel.

  Use three AAA cells, not four, if using a PIC.  Or use four and a
diode or two in series with the PIC, not the lamp.  You don't really
want white light for a candle anyway!
--
  Cheers,
        Paul B.