On 18/02/11 21:50, Hal Murray wrote:
My guess is something is broken rather than the chip has been wiped. Have
you checked the chip select or data path?
Seems unlikely. The board hasn't been touched. The chip seems to connect
directly to the bus connector (some weird high-density IDC thing).
If it's the MAC address, it's unique to each board. Do you remember the old
one?
It's printed on the bottom of the board.
In the early Ethernet days, the MAC address was typically stored in a small
ROM. Since even the smallest ROM chips available had lots of room they added
some other stuff. A description of the format is probably available online
and/or you can probably decode it from some driver software that reads the
ROM.
Um, this thing runs custom software, a custom RTOS... custom everything.
If it ran (say) uCOS or CP/M with a standard Ethernet driver and stack,
then maybe it'd be doable.
I doubt if there is a simple way. Why would you want to do that? The idea
is that each board should have a unique MAC address. You want to make it
hard for idiots to do things like copy an address and destroy that uniqueness.
The 1670G (a later HP analyser) allows this -- if the EEPROM gets nuked,
it'll set the MAC to all zeroes and disable the LAN adapter. You can
then go into System Settings and a new Factory Options button appears.
You push that, and it asks you for the MAC address from the LAN card
sticker.
The boards typically disabled the write-enable pin. The chips were
programmed before getting soldered down.
This one almost certainly wasn't!
Every other programmable device in the analyser has a thermal-transfer
label (most of them seem to be Kapton-backed, a few are paper). This
parallel EEPROM is the only one which doesn't have a label -- at all.
Just the manufacturer branding...
--
Phil.
li...@philpem.me.uk
http://www.philpem.me.uk/
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