For up to 30 boards I'm sure you don't need a random start.
The answer is a daisy-chain connection, the n+1 board will start only
after then board n has start. The whole starting time could be under
5...30 seconds, but this depends on what you have on the boards.

Vasile

On Tue, 14 Aug 2001, 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
>
> --
> http://www.piclist.com hint: The list server can filter out subtopics
> (like ads or off topics) for you. See http://www.piclist.com/#topics
>
>

--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.