I've done this, makes a good RF broad band signal source.  I use
Zeners though.

Fred Thompson
fthompso@mail.win.org

On Thu, 4 Sep 1997, Andrew G Williams wrote:

> I'll shortly need to use a 16F84 to generate a series of random pulses (truly
> random, not generated by a pseudo-random algorithm). Does anyone know a
> straightforward way of doing this?
>
> I suppose the usual approach is to pass a low current through a diode,
> amplify the noisy output and then produce pulses from a comparator (but
> please correct me if that's wrong). I was wondering if the PIC itself
> contains any inherent noisy or random signals, or can be persuaded to. If so,
> genuine random pulses could perhaps be generated without any extra
> components.
>
> Then again, I could use one with a built-in ADC or comparator. If I did that,
> would the noisy signal need amplifying before being input to the PIC? I can't
> find anything in the application notes about these things, so any advice
> would be appreciated.
>
> Andy W.
>