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AR# 24258

Platform Cable USB - "ERROR: Write Command Buffer Failed ..." occurs in iMPACT when initializing the cable


When iMPACT tries to detect the Platform Cable USB, the following error occurs: 


"write command buffer failed <8 digit number>" 


Why does this occur?


This is an intermittent problem that some computers have with the Platform Cable USB. This problem only occurs because of an issue with the USBl Port. The Parallel Cable is not affected by this problem; therefore, it can be used at 6 MHz as a way to work around this issue. 


First, make sure the latest version of the software is being used. The software updates can be found by selecting Download at the top of the Xilinx Homepage. 


Second, check to see what other applications could be using the USB ports. These would include printers, USB Dongles, or other applications. If these processes are running, please kill these processes and try the cable again. 


Third, check to see if a USB splitter is being used. These devices cannot be fully tested by Xilinx and cannot be fully supported.  


If you are still experiencing problems, contact Xilinx Technical Support: 



When opening a case, please include the XINFO report, "impact.log" file showing the problem and the markings from the cable. 


The XINFO report is produced by using the XINFO System Checker software that is installed as an application with the ISE design tools. This application will record a log of the files installed on the system as well as a specification of the hardware being used. 


The "impact.log" file contains all of the warning messages that are in the iMPACT window. This file is created from the location iMPACT was opened from. To open iMPACT from a given directory, open up a command prompt and "CD" into the desired directory. Type "impact" and the tools will be launched from the desired location creating a log file in this directory.  


The support team will also need to know if the cable is a Low Power / Pb-free version of the cable.

AR# 24258
Date Created 09/04/2007
Last Updated 05/20/2014
Status Archive
Type General Article