I posted this a few days ago, but I think the server ate it.
Here goes one more try:


Have you considered the Dallas DS2401 ( http://www.dalsemi.com/DocControl/PDFs/2
401.pdf ) ?

I recently used it to provide a "MAC" address for each of the nodes on a multidr
op RS-485 network.
It saved me the effort of trying to serialize the programed PICs.  Each device c
ontains a 48 bit unique ROM serial number.  They are prices at about $1.50 in sm
all quantities.  Another nice thing about these is that they only require one bi
-directional I/O pin to access.

Dallas also includes the serial number in each of their 1-wire devices. If you a
re using one of their 1-wire thermo. sensors, you already have you serial number
.

If you device communicates with the world via a display or serial link, why not
hold down a button or the like during power on to place the unit in a diagnostic
 mode where the serial number and any other parameters could be accessed?


-mgresham


At 01:56 PM 8/26/98 -0500, you wrote:
>        Maybe somebody already suggested this, but what about an ink
>stamp that puts the serial number on the board in resist ink or
>exposes an area to light as in contact imaging so that when the board
>is etched, the printing is left in copper.  Since it is designed to be
>read by humans, it wouldn't matter if it was copper over the board
>material or the opposite which would be letter-shaped holes in the
>copper.
>
Michael Gresham, KE4SWX
mgresham@spsu.edu

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