> At 17:17 13/05/97 +0000, you wrote:
> >I need a routine that returns a random number to implement something similar
> >to CSDMA/CD. I need it to make a random wait time after a collision, i've
> >seem some routines but how do i get different seeds to inicialize the
> >routine ?
>
>  Hello,
>  I've found that performing a XOR operation with all the un-inisialized
> values of the user RAM at startup (in the PIC16C84), you get a good random
> seed.

Yes, but if two PICs happen to XOR to the same value you're sunk.  Even
using a 2-byte XOR of user RAM is no guarantee of safety; depending upon
the characteristics of the chips you may find that certain chips tend
toward the same stuff.  For a CSDMA/CD application, that would be a
killer.