Specifications

260 www.xilinx.com Development System Reference Guide
Chapter 14: BitGen
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Note: For more information on encryption, see the Answers Database at the following web site:
http://www.xilinx.com/support.
BitGen Options
Following is a description of the command line options and how they affect the behavior of
BitGen.
Note:
For a complete description of the Xilinx Development System command line syntax, see
“Command Line Syntax” in Chapter 1.
–b (Create Rawbits File)
Create a rawbits (file_name.rbt) file. If the –g Readback option is specified in combination
with the –b option, an ASCII readback command file (file_name.rba) is also generated.
.msd An ASCII file that contains only mask information for
verification, including pad words and frames. No commands
are included. Produced when -g Readback is specified.
.msk A binary file that contains the same configuration commands as
a .bit file, but has mask data where the configuration data is.
This data should NOT be used to configure the device. If a mask
bit is 0, that bit should be verified against the bit stream data. If
a mask bit is 1, that bit should not be verified. Produced when
the -m option is specified.
.nky An ASCII file that contains key information for Virtex-II devices
when encryption is desired. This file is used as an input to
iMPACT to program the keys. Produced when -g Encrypt:Yes is
specified.
<outname>_key.isc Contains the data for programming the encryption keys in IEEE
1532 format. Produced when -g IEEE 1532:Yes and -g
Encrypt:Yes are set.
.rba An ASCII file that contains readback commands, rather than
configuration commands, and expected readback data where
the configuration data would normally be.
To produce the .rba file, the –b option must be used when –g
Readback is specified.
.rbb The same as the .rba file, but it is a binary file.
Produced when –g Readback is specified.
.rbd An ASCII file that contains only expected readback data,
including pad words and frames. No commands are included.
Produced when -g Readback is specified.
.rbt An ASCII version of the bit file. Produced when the -b option is
specified.
Table 14-1: BitGen Output Files
Output File Type Output File Description