From: Humphreys, David (david.humphreys_at_honeywell.com)
Date: Fri Jun 29 2001 - 05:51:56 PDT
> > I believe it calculates the ID from the CPU serial number.
>
> Is that a really unique number, or is it equal for a series of CPUs?
>
> Eckard
Eckard,
You are absolutely correct.
The SA-110 has a device identification code register.
No programmable supplementary identification code is provided.
It's a 32-bit register.
Bits 31 thru 28 carry the version
Bits 27 thru 12 carry the part number
Bits 11 thru 00 carry the JEDEC code
Bits 27 thru 00 are always 0x102C06Bh
So, despite the fact that the CPU has an ID number, it is the same
for a particular version of the device and cannot serve as a unique
identifier.
The DS2401 performs this function. No two chips have the same number
as they are sequentially programmed at manufacture.
It is a one-wire serially accessed 64 bit number.
Bits 63 thru 56 8 bit CRC
Bits 55 thru 08 48 bit serial number
Bits 07 thru 00 8 bit family code (01h)
Regards,
David Humphreys
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