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Development System Reference Guide www.xilinx.com 295
IBISWriter Input Files
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IBISWriter Input Files
IBISWriter requires a design source file as input.
• FPGA Designs
Requires a physical description of the design in the form of an NCD file with a .ncd file
extension.
• CPLD Designs
The input is produced by CPLDfit and has a .pnx file extension.
IBISWriter Output Files
IBISWriter outputs an .ibs ASCII file. This file comprises a list of pins used by your design,
the signals internal to the device that connect to those pins, and the IBIS buffer models for
the IOBs connected to the pins. The format of the IBIS output file is determined by the IBIS
standard. The output file must be able to be validated by the Golden Parser to ensure that
the file format conforms to the specification.
Note:
IBISWriter gives an error message if a pin with an I/O Standard for which no buffer is available
is encountered, or if a DCI value property is found for which no buffer model is available. After an error
message appears, IBISWriter continues through the entire design, listing any other errors if and when
they occur, then exiting without creating the .ibs output file. This error reporting helps users to identify
problems and make corrections before running the program again.
IBISWriter Options
This section provides information on IBISWriter command line options.
–allmodels (Include all available buffer models for this architecture)
To reduce the size of the output .ibs file, IBISWriter produces an output file that contains
only design-specific buffer models, as determined from the active pin list. For users who
wish to access all available buffer models, the –allmodels command line option should be
used.
Use the following syntax when using the –allmodels option:
ibiswriter –allmodels infile outfile.ibs
–g (Set Reference Voltage)
The –g command line option varies by architecture as shown in Table 17-1.
Use the following syntax when using the –g option:
ibiswriter
–g option_value_pair infile outfile.ibs
The following is an example using the VCCIO:LVTTL option value pair.
ibiswriter –g VCCIO:LVTTL
design.ncd design.ibs
The –g option supports only the architectures listed in the following table: