iMPACT
Assigning a New Configuration File
To Assign a New Configuration File
  1.  Select Edit > Assign Configuration File, or right-click on the device and select Assign Configuration File.
  2.  In the Assign New Configuration File dialog box, select a folder and file.
    Assigning Configuration Files
    There are several types of configuration files. A Bitstream file (*.bit) is used to configure an FPGA. A JEDEC file (*.jed) is used to configure a CPLD. A PROM file (*.mcs or .exo, ) is used to configure a PROM and to program FPGAs in Slave Serial mode. A Raw Bit File (*.rbt) is an ASCII version of the Bit file. The only difference is that the header information in a Bit File is removed from the Raw Bit File. An IEEE1532 file (*.isc) can be used to configure selected FPGAs, CPLDs, or PROMs.
    After initializing a chain or adding a device, you are prompted for a configuration file. This is the file that is used to program the device. If a configuration file is not available, a Boundary-Scan Description File (BSDL or BSD) file can be applied instead. The BSDL file provides necessary Boundary-Scan information that enables a subset of the Boundary-Scan operations to be available for that device.
    To select a BSDL file, change the file type to *.bsd in the Assign New Configuration File window and browse to the BSDL file. BSDL files for Xilinx® devices are located in the $Xilinx\<device>\data directories. For example, if the software is installed in c:\xilinx, the BSDL file for a Virtex device is in c:\xilinx\virtex\data.
    Selecting a BSDL File
    For Xilinx devices, you do not have to associate a BSDL, JEDEC, or bit file with devices that you only wish to place in bypass mode. Click Cancel in the Assign New Configuration File dialog box. When any chain operation is attempted, an automatic search is conducted in the Xilinx directories for the correct BSDL file and places the device in bypass mode.
    For non-Xilinx devices, a BSDL file must be supplied in Boundary-Scan mode. The BSDL file is typically obtained from the vendor of the device. If a BSDL file cannot be obtained, a generic BSDL file can be created. When a non-Xilinx device is added, you are asked if a BSDL file exists for the device.
    If yes, you can browse to the file. If no, you are asked for the device name and the Instruction Register Length. This minimal amount of information enables a generic BSDL file to be created and enables the device to be put in BYPASS or HIGHZ. Check with the vendor of the device to obtain the instruction register length.

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