Answers Database

XC9500: Difference between all the checksums for the 9500 family


Record #3214

Product Family:  Hardware

Product Line:  9500

Problem Title:
XC9500: Difference between all the checksums for the 9500 family


Problem Description:
Keywords: checksum, 9500, jedec

Urgency: Standard

General Description:

There are three different checksums associated with the XC9500
devices. What are those?


Solution 1:

The XC9500 JEDEC files have two checksums as defined by the JEDEC
standard. The Last line in the JEDEC file beginning with the ^C
character is the file checksum. The second to last line in the
JEDEC file beginning with a C and ending with an * is the Fuse
checksum.

The JEDEC File checksum is the sum of only the actual programmed
bit locations in the device adjusted into eight bits (as
specified in the JEDEC file). The JEDEC checksum is therefore
missing some device bit locations in its calculated checksum.

The EZTag/JTAG Programmer softwares report a third checksum, which
is actually a sum of all the eight bit programmed bytes in the
device (as read back directly from the device without any
adjustments). This checksum includes all the programmable bits in
the device and is completely different from the JEDEC file
checksum.



End of Record #3214