We use Microchip PIC16C711. How (if possible) can we give each unit a serial
number in ROM?

----- Original Message -----
From: "Douglas Butler" <dbutler@IMETRIX.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, August 16, 2001 1:56 PM
Subject: Re: [PIC]: Generating a "truly" random number on the application of
power


> If you give each unit a serial number in ROM you can use that to delay
> the start.  Dallas makes tiny one wire interfaced chips that have serial
> numbers in them that are guaranteed to be unique.
>
> Sherpa Doug
>
> > -----Original Message-----
> > From: Nikolai Golovchenko [mailto:golovchenko@MAIL.RU]
> > Sent: Thursday, August 16, 2001 1:45 PM
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: [PIC]: Generating a "truly" random number on the
> > application of power
> >
> >
> > Tony,
> >
> > You could try to use a few unitialized RAM locations. On power-up,
> > they would probably contain random values. But the problem is that
> > the compiler clears all registers on power-up, so the start-up
> > routine should be modified, which might be tricky though...
> >
> >  Nikolai
> >
> > Tuesday, August 14, 2001, 10:17:59 AM, Tony Pan wrote:
> > > 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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