Our boards have serial numbers, but the software has no knowledge of that
serial number unless we add some components onto the board but I don't think
the company wants to do it.

Tony

----- Original Message -----
From: "Pfaff, John" <pfaff@WRITEME.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, August 16, 2001 1:50 PM
Subject: Re: [PIC]: Generating a "truly" random number on the applicationof
power


> Do your boards have serial numbers, and (if so) does the software have
> knowledge of that serial number?  If so you could base a startup-delay
> on, say, the last digit of the serial number, giving you ten different
> delays (just for example).
>
> Tony Pan wrote:
> >
> > Mike,
> >
> > I guess it's more economic to do it in software rather than in hardware.
> > (It's a commercial product.)
> >
> > It 's OK to allow a handful of boards to start at the same time. What we
> > want to avoid is that all the boards (20, 30 or more) to start at the
same
> > time.
> >
> > Tony
> >
> > ----- Original Message -----
> > From: "Dipperstein, Michael" <mdippers@HARRIS.COM>
> > To: <PICLIST@MITVMA.MIT.EDU>
> > Sent: Thursday, August 16, 2001 1:26 PM
> > Subject: Re: [PIC]: Generating a "truly" random number on the
application of
> > power
> >
> > > Why not just delay the application of power to each board?  If you
have a
> > > control pin to spare, you can build a system that where it's the job
of
> > each
> > > board to allow power to flow to the next.
> > >
> > > In any random number scheme, you still have the possibility that all
> > generators
> > > will generate the same number and come up at the same time.  This
can't
> > happen
> > > when it's the job of one board to apply power to the next.
> > >
> > > -Mike
> > >
> > >
> > > -----Original Message-----
> > > From: Tony Pan [mailto:weidong.pan@verizon.net]
> > > Sent: Tuesday, August 14, 2001 10:18 AM
> > > To: PICLIST@mitvma.mit.edu
> > > Subject: [PIC]: Generating a "truly" random number on the application
of
> > > power
> > >
> > >
> > > Hi,
> > >
> > > In our project, several identical boards are connected together.
Normally,
> > > on the application of power, they will be turned on at the same time
and
> > > starting running at the same time. But we don't want that to happen.
If
> > all
> > > boards are running at the same time, they will consume too much power
and
> > > cause a problem.
> > >
> > > So, we want to impose a lockout time at the beginning of the software;
the
> > > lockout time should be random for each board (though they use the same
> > > software). Only after the lockout time expires would the program start
> > > running. Thus the boards will start at different time and won't cause
a
> > > power shortage.
> > >
> > > My question is: how to generate a "truly" random number on the
application
> > > of power. The number should not be determined upon the compilation of
the
> > > software, but should be upon the initial powerup of the chip. (Or, it
> > should
> > > be determine by each individual chip.)
> > >
> > > Help?
> > >
> > > (By the way, I write my program in C and use PICC compiler.)
> > >
> > > Thanks in advance.
> > >
> > > Tony Pan
> > >
> > > --
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> > >
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