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PROGRAMMERS: checksums on Data I/O programmers may not match when doinga "load" and doing a "read"


Record #930

Product Family:  Hardware

Product Line:  1700

Problem Title:
PROGRAMMERS:  checksums on Data I/O programmers may not match when
doinga "load" and doing a "read"



Problem Description:
Checksums on Data I/O programmers may not match when doing a
"load" and doing a "read".  "Load" operations are done prior
to programming a part, while "read" can be done at any time
before or after the part is programmed.


Solution 1:

This is because the Data I/O checksum algorithms for "load"
and "read" operations differ.  When calculating the checksum
after a "load", Data I/O includes the manufacturer's ID in its
calculation.  The manufacturer's ID is also included in the
calculation when the checksum is calculated at the
end of the programming process. However, Data I/O does not
include this data when it calculates the checksum after a
"read".

This applies to our 1700 and 7000 devices as well.

This may pose a problem for some customers who want to be able
to get the same checksum for both operations.  There is no
workaround for this, but the user may take some level of
comfort in knowing that they should see the same checksum
within the confines of what may be considered a single
"operation"--that is, the checksum they get when they load a
programming file to program a device, and the checksum they
see at the end of programming should match, and the checksum
they get when they read a device as a master, and when they
immediately program a part using the same master, should also
match.

For details on the actual checksum calculation algorithms
used by a specific manufacturer (e.g., Data I/O), contact
that manufacturer directly.  Note that this information
may be proprietary in nature.



End of Record #930