3421A CAL RAM

[Dave Frederickson]

Excellent!

So perhaps the 3421A is sending a string as well. Sure enough! 256 characters in this case.
3421A:
O@@@@@@@@@@@@@@@
IIIIIHHOMCADNCED
IIIIIIIOMDMBOOLC
@@@@@AAONADDNNDG
@@@@@@AONB@OOBDL
@@@CEDE@AMLDMNLO
IIIIIIA@@EMLOJGG
IIIIIII@AKAOOBLD
IIIIIII@ALNAODM@
IIIIIII@ALMCOEMG
IIIIIII@AKDOOGLD
IIIIIII@@ANLOENG
@@ABAIH@@@@@DGDG
IIGIDHG@@@@@MHEC
IIGHDIG@@@@@MHDG
OOOOOOOOOOOOOOOO

A description of electronic calibration can be found in the same issue of the HP Journal in the 3468 article.

What is known:
* There are two constants per Function/Range. Zero (offset) and Gain. The default value for Zero is zero and Gain is one.
* There are a total of 12 sets of calibration constants saved for the 3468 and 14 for the 3421.
* The RAM was mapped is such a way that the constants for a each Function/Range would be in a unique row in RAM. This was so that if there was an ESD event while Write (CAL) Enable was true then it would only affect one Function/Range, minimizing the recalibration task.
* The RAM device is physically organized in a 32x32 array, so room for 14 sets of 64-bit calibration constants
* Each Function/Range constant includes parity. There is also a checksum. If the checksum is in addition to parity or the same as, I don't know.

So now the task is to calibrate one constant at a time and then examine the cal data to determine where the constants for each Function/Range are mapped. Then, figure out how the constants are encoded.

Any help would be appreciated.

Thanks, Dave