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HP 856X Battery Backup and Various Memory Questions

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dfnr2:
Almost certainly the cal data is in EEPROM.

Electro Fan:

--- Quote from: dfnr2 on May 15, 2015, 10:08:36 pm ---Almost certainly the cal data is in EEPROM.

--- End quote ---

If the data is in EEPROM - which is typically (always?) non-volatile - why does it need to be backed-up with a battery?  Plus, how does a user write new cal data to EEPROM?  EEPROM would seem like a nicely secure place to put cal data but maybe the cal data winds up in SRAM since SRAM is designed to be used with battery backup?  I don't know, just conjecturing...

Electro Fan:

--- Quote from: Electro Fan on May 15, 2015, 10:22:52 pm ---
--- Quote from: dfnr2 on May 15, 2015, 10:08:36 pm ---Almost certainly the cal data is in EEPROM.

--- End quote ---

If the data is in EEPROM - which is typically (always?) non-volatile - why does it need to be backed-up with a battery?  Plus, how does a user write new cal data to EEPROM?  EEPROM would seem like a nicely secure place to put cal data but maybe the cal data winds up in SRAM since SRAM is designed to be used with battery backup?  I don't know, just asking/conjecturing...

--- End quote ---

dfnr2:

--- Quote from: Electro Fan on May 15, 2015, 10:22:52 pm ---If the data is in EEPROM - which is typically (always?) non-volatile - why does it need to be backed-up with a battery?  Plus, how does a user write new cal data to EEPROM?  EEPROM would seem like a nicely secure place to put cal data but maybe the cal data winds up in SRAM since SRAM is designed to be used with battery backup?  I don't know, just conjecturing...

--- End quote ---

The Cal data is altered only during service, and is not meant to be modified or backed up by the user.  It also should not be lost when the removable battery is taken out to clear the user data (programs, traces, etc.)  Looking in the manual (page 7) confirms that the Cal/config data is in EEPROM.  Of course, if the EEPROM is removable (or even if it's just accessible), I think it would be prudent to back it up anyway.

This is different from the 859xE SA's, which have no EEPROM, and have a battery permanently mounted on the PCB.  Since it can't be removed casually, the risk of casually erasing cal data is small, although these SA's do have a procedure for backing up the cal data in case of battery failure.  Such a  procedure is not necessary (and not described) for the 856XE series.

Electro Fan:

--- Quote from: dfnr2 on May 18, 2015, 11:10:20 pm ---
--- Quote from: Electro Fan on May 15, 2015, 10:22:52 pm ---If the data is in EEPROM - which is typically (always?) non-volatile - why does it need to be backed-up with a battery?  Plus, how does a user write new cal data to EEPROM?  EEPROM would seem like a nicely secure place to put cal data but maybe the cal data winds up in SRAM since SRAM is designed to be used with battery backup?  I don't know, just conjecturing...

--- End quote ---

The Cal data is altered only during service, and is not meant to be modified or backed up by the user.  It also should not be lost when the removable battery is taken out to clear the user data (programs, traces, etc.)  Looking in the manual (page 7) confirms that the Cal/config data is in EEPROM.  Of course, if the EEPROM is removable (or even if it's just accessible), I think it would be prudent to back it up anyway.

This is different from the 859xE SA's, which have no EEPROM, and have a battery permanently mounted on the PCB.  Since it can't be removed casually, the risk of casually erasing cal data is small, although these SA's do have a procedure for backing up the cal data in case of battery failure.  Such a  procedure is not necessary (and not described) for the 856XE series.

--- End quote ---

In the manuals (856XE/EC User's Guide and 8590E/L User's Guide) at the links below it looks like page 7 is part of the Table of Contents - maybe you are referring to a different manual? 

http://cp.literature.agilent.com/litweb/pdf/08560-90158.pdf
http://www.sonoma.edu/esee/manuals/08590-90301.pdf

Anyone have any idea where a cal backup procedure for the 856XE (if there is one) might be documented?

Thanks

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