[Techtoolslist] Fluke 9100 system EEPROM disambiguation

[Andrew Welburn]

hi all.

  There's a 32-byte soldered-in I2C serial EEPROM (type X2444) that 
contains crucial hardware setup information use in the Fluke 9100 series 
systems. The values in this eeprom hold information pertaining to some 
calibrations as well as all basic I/O hardware. This information can all 
be set/changed with the use of floppy service disks in a working system.

  If you happen to set the wrong floppy drive type in this menu, you can 
lock yourself out of being able to adjust anything, as well has having a 
non-working floppy drive.

  You can re-program the chip in-circuit (in theory, but i didn't try 
it) or you can de-solder it, and dump the contents/reprogram it. The 32 
bytes might be a little cryptic, but with trial an error i have found 
out the following address map. It is not exhaustive, there are likely 
more things stored in here relating to IO mod or pod or probe 
calibrations accessed in the setup/calibration menus from a regular boot 
cycle, but for now, this is what i have discovered:

offset 		Purpose			Notes
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
00 to 03	Serial #		Little Endian
04		System/disk type	Note1
05 to 08	Probe offset		calibration values
0A		Disk err reporting	00=OFF 0A=ON
0C,0D		unknown			do not change
0F		RAM size		Note2
11		Network Node		00 to F4 is valid
15		Floppy type		Note3
18 to 19	IEEE option		YES=04D7 NO=14D7
1A to 1C 	site #			Little Endian
1E to 1F	checksum		Note4

Note1 = 42=9100/Miniscribe 76=9100/scsi512 66=9100+scsi256 00=9105/9050

Note2 = 18=1.5mb 20=2mb 30=3mb 40=4mb 80=8mb F0=15mb

Note3 = 00=Gotek 01=Canon 03=Sony 04=Mitsumi 05=Teac 06=CanonHD

Note4 = BSD Checksum, but barrel-rotated right 10 bits then inverted 
see: http://www.andysarcade.net/personal/tech/fluke9100/andysum.zip

  Big props to TheMogMinor/MooglyGuy for figuring out the checksum, as 
well as writing the utility and providing source code!

  Now you can create a binary yourself, generate/apply a valid checksum 
and write this to the ROM and get yourself back in business.

enjoy.


-- 
Andrew Welburn
andys-arcade