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AR# 15089

8.1i iMPACT, 18V00, CPLD - What is Automatic Checksum Insertion (Autosignature Generation)?

Description

What is Automatic Checksum Insertion (Autosignature Generation), and how do I use it?

Solution

The Automatic Usercode insertion feature has been added to iMPACT in the 5.1i design tools release. This feature provides you a tool for PROM and JEDEC file-revision control.

For CPLDs, the checksum of the Jedec file is inserted into the signature/usercode area of the device. This enables you to easily compare the usercode data with the calculated checksum to verify that the program stored in the CPLD is correct.

PROM

1. (PROM)

Use iMPACT to generate a PROM file. A ".sig" file will appear in the same directory as the new PROM file.

The ".sig" file will contain text similar to the following:

// PROMGEN: Xilinx Prom Generator F.23

// Copyright (c) 1995-2002 Xilinx, Inc. All rights reserved.

DATE 07/29/02-11:45

SOURCE C:\Xilinx\ISEexamples\watchvhd//test.mcs

DEVICE XC18V01

SIGNATURE 0x012B700A

(CPLD)

6.1i and newer:

1. For CPLDs, the usercode needs to be embedded into the JEDEC. This can be done by selecting the "Autosignature Generation" option in the Generate Programming File property within the Project Navigator. This will add a line near the bottom of the JEDEC file:

Example:

Jedec Example
Jedec Example

The line starting with "C" is the fuse checksum.

The line starting with "U" is the usercode that matches the fuse checksum.

The last line is a file checksum.

2. To enable Auto Checksum Insertion in iMPACT, go to Edit -> Preferences and select "Automatic Checksum Insertion (CPLD & PROM)."

With this option selected, iMPACT will automatically program the PROM or CPLD Usercode field with the Usercode value in the SIGNATURE field in the JEDEC file.

3. Program the PROM or CPLD as usual: Add the PROM or JEDEC file in iMPACT Boundary Scan or File Generation Mode, select the part, and select Operations -> Program. No special options must be selected in the "Program Options" window; do not select the "PROM/CoolRunner-II Usercode" or "XPLA UES" boxes.

4. To verify that the signature was programmed properly, select the device in iMPACT, then use Operations -> Get Device Signature/Usercode.

5.1i:

For CPLDs, the ".sig" file must be generated with the ISE design tools. To enable ".sig" file generation, select "Autosignature Generation" in the Generate Programming File property within the Project Navigator.

The ".sig" file will contain text similar to the following:

DATE 23/10/02-15:37

SOURCE top.jed

DEVICE XC95144XV-4-TQ100

SIGNATURE 0x00003B83

The DATE, SOURCE, DEVICE, and SIGNATURE fields will vary, depending on the options you have selected. The SIGNATURE field contains the checksum value for the PROM or JEDEC file. The checksum value will change if the same file is placed in a different sized PROM or if a different fill value is selected during PROM file generation.

2. To enable Auto Checksum Insertion in iMPACT, go to Edit -> Preferences and select "Automatic Checksum Insertion (CPLD & PROM)."

With this option selected, iMPACT will automatically program the PROM or CPLD Usercode field with the value in the SIGNATURE field in the ".sig" file.

3. Program the PROM or CPLD as usual: Add the PROM or JEDEC file in iMPACT Boundary Scan or File Generation Mode, select the part, and select Operations -> Program. No special options must be selected in the "Program Options" window; do not select the "PROM/CoolRunner-II Usercode" or "XPLA UES" boxes.

iMPACT will look for a ".sig" file in the same directory as the source PROM or JEDEC file and automatically program the USERCODE field with the SIGNATURE value from the ".sig" file. The ".sig" file must have the same file name as the source PROM or JEDEC file.

4. To compare the signature of a programmed device to a ".sig" file, select the device in iMPACT, then use Operations -> Get Device Signature/Usercode.

AR# 15089
Date Created 09/03/2007
Last Updated 12/15/2012
Status Active
Type General Article