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Answers Database
SPROMS: Checksums: What are the PROM file and programmer checksums?
Record #1179
Product Family: Hardware SPROMS: Checksums: What are the PROM file and programmer checksums? Problem Description: Urgency: standard General description: The question often arises as to how one can verify the correctness of a PROM file checksum. The answer is that Xilinx does not disseminate information on checksum calculation algorithms. Such algorithms are unique to each PROM programmer vendor. They may even diverge from Xilinx's guidelines on incorporating the reset polarity fields-- for example, Data I/O programmers include the RESET polarity addresses in their checksum calculations, whereas Xilinx programmers do not. Solution 1: The best that users can do is verify that they get the same checksum every time they download the same PROM file (for example, the MCS file, if that is the format they are using), using the same programmer and version of the vendor's programmer software. Short of hand-calculating the checksum itself, there is no good way to verify that a given checksum is correct. However, if you can consistently get the same checksum immediately after programming the part, as well as when you subsequently do a read of the PROM's contents, this provides a good level of confidence that the PROM is programmed with the proper data. To ensure that the matching of checksums during these two steps in the process is meaningful, you must fill the programmer memory with FF hex both before downloading the PROM file, as well as before you do a read of the PROM contents. End of Record #1179 - Last Modified: 12/15/99 14:41 |
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