NVRAM dump by tektool vs. tdsNvramFloppyTools_v4
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1. Environment preparation
TDS754D (resistors / caps upgraded to TDS784D, some SW options upgraded)
Setup the scopes GPIB address to "1"
PC (Windows 98) equipped with NI488 PCII ISA GPIB card and connect the scope (by GPIB) with the PC
(The GPIB tools/environment needs to be set up correctly on that PC)
You do need the "tektool" on that PC
Prepare a floppy (formated by the scope itself and copy the respective two files from tdsNvramFloppyTools_v4 onto that floppy
You may or may not attach a console adapter to see any possible erasing message
2. TDS preparation (optional - may ease the compare later on)
You need the tool "TDSError Log Viewer" to erase the error logs on
Switch the scope on (in normal mode)
Use the "TDSError Log Viewer" to clear the error logs
Delete all "secure" files on the scope - so waveforms stored etc.
(TDS: "Utility" --> "Config" --> "Tek Secure Erase Memory" --> "OK Erase Setup & Ref Memory")
Perform a factory reset (TDS: "Setup" --> "RECALL Factory Setup" --> "OK Confirm Factory init")
3. Execution (in a row)
a) Scope is OFF
Put NVRAM write protection SW in position "protection OFF / Monitor mode"
Switch the scope ON and wait shortly (it's taking only seconds until it's booted to the "monitor" SW.
(Remember: The scope seems to "hang" and has nothing on the screen what's absolutely correct)
dump NVRAM by tektool
Switch the scope OFF again
Put NVRAM write protection back into "protection ON"
b) Place the floppy prepared with the tdsNvramFloppyTools_v4 into the scopes drive
Switch the scope ON and wait until the tool completed the dump...
dump NVRAM by tdsNvramFloppyTools_v4
Drop the floppy out of the scope
Switch the scope OFF
c) Put NVRAM write protection SW in position "protection OFF / Monitor mode"
Switch the scope ON and wait shortly (it's taking only seconds until it's booted to the "monitor" SW.
(Remember: The scope seems to "hang" and has nothing on the screen what's absolutely correct)
dump NVRAM by tektool
Switch the scope OFF again
Put NVRAM write protection back into "protection ON"
4. Compare
Now having the 3 results let us prepare the compare.
The tektool usually giving you separate files for TIMEKEEPER and SRAM.
For an easy compare we should link the two files after each other (first TIMEKEEPER than append SRAM).
This can performed by many tool - e.g. just binary copy /b file1.bin + file2.bin resulting_file.bin
Now we do have 3 equally sized files which we are able to compare easily.
If we do compare the first and the last one (both done using tektool) you can see that there are only small differences.
There are always small changes, e.g. the real time clock at the start of the files but also some GUI settings which are stored.
Also if there are any errors the scope will log these during startup.
Back to the comparison having a look on the first and the last dump we do see some slight changes (normal as described above).
If we do compare one of the tektool dumps against the dump performed by the tdsNvramFloppyTools_v4 (taken as second dump so between the
two above in a timely manner) we do see a lot more differences - some seem to have "more" content in the dump done by the tektool, some
in the dump done by the tdsNvramFloppyTools_v4. Because lot of the changes between the first (tektool) dump and the second (tdsNvramFloppyTools_v4)
dump seem to be gone in the thired (second tektool) dump this seems not to be content just created / changed during the startups
there seems to be an inconsistence between the dumps taken by the tektool vs. taken by the tdsNvramFloppyTools_v4.
Does maybe the "NVRAM protection switch" does have any influence on the NVRAM content also if it's only read???
Lets try a fourth dump using the tdsNvramFloppyTools_v4. This time we'll have the tdsNvramFloppyTools_v4 floppy in the scopes drive and
the NVRAM protection switch still "ON" when switching on the scope but as soon as we see the floppy LED flash for the first time
we do change the NVRAM protection switch to "OFF" so the dump taken using the tdsNvramFloppyTools_v4 is done while having the
NVRAM protection switch OFF.
After the dump is done (you'll recognize when the floppy is finished to write data - it seems sometimes the "finished" dialog
of the tdsNvramFloppyTools_v4 is not in that configuration) we drop of the floppy and switch of the scope. Do not forget to switch the
NVRAM protection switch to ON again. If that switch does not make any difference in reading the NVRAM than the fourth dump should only
have slight differences to the second one (also made using the tdsNvramFloppyTools_v4) which will mean that the dumps made using
the tdsNvramFloppyTools_v4 are inconsistent with the ones made using the tektool and therefor maybe faulty. If that fourth dump has
the same bigger differences like the tektool ones compared with the tdsNvramFloppyTools_v4 ones this shows that having the
MVRAM protection switch in one or the other position DOES IN FACT make a big difference in the memory read.
I did so and found the fourth dump does also have bigger differences to the second dump (both made using the tdsNvramFloppyTools_v4)
but the fourth dump has also bigger differences compared with the tektool ones. What does that mean???
Ones for sure: Dumps differ very much between having the NVRAM protection switch in ON or OFF position!
But where do that big differences come from between having the NVRAM protection OFF doing a dump using tdsNvramFloppyTools_v4 and a dump
done using the tektool?