I have the Logic Analyzer hooked up, and with the clue about the Fluke storing the Sig at F345 and F346 I can generate 1,000 instructions prior to and including the signature data dumped to it's storage locations. There are a few routines in there that are RR and SRL with a check and then repeats about six times and wanders off to some subroutines and comes back and hammers the loop again. I can dump this via the RS-232 port and was testing the signature with both a one byte wide (11) and two byte wide (11 11) chunks of data that I stuffed into RAM and then ran the ROM Sig on the RAM locations. Interestingly enough if there is only one data byte then the process is different than if there are two or more bytes. So I think what I'll do is store, backwards, as much as I can on a flat text file and either send it to whoever wants it or post it to the FTP site. This shouldn't take long, and there is a recurring loop when the 9010 is waiting for keypress that I will use as the starting point. I will only make it a two byte wide (11 11) signature for simplicity. I will go back further than 1,000 instructions by finding an instruction to trigger on earlier in the stream... John :-#)# At 08:39 PM 08/05/2002 -0400, Kev wrote:
This idea doesn't work either since (look below)
Okay, a checksum on a single byte of FF yeilds an FF
I found this to be interesting......
Byte 0 = F3 Sig = FE Byte 1 = 3E Sig = 1EE8 Byte 2 = 00 Sig = 1EE8 Byte 3 = ED Sig = 225A Byte 4 = 47 Sig = 56B6
Byte 12 = ?? Sig =910E Byte 13 = 00 Sig = 20F6
It isn't using the last read byte as the divisor is it?
Kev
"Rom Signature is a four-digit HEXADECIMAL number that is a shorthand representation of the data obtained in an area of ROM memory. The ROM signature is obtained by successively dividing the data in ROM by a binary number (they DON't say what the @!$%#$@% number is! - JR). The resulting signature identifies the data from which it is obtained, and provides a convenient way of" (....blah blah, no other description of the process)."