MAP Files

This section describes the MAP input and output files.

Input Files

MAP uses the following files as inputs.

• NGD file - Native Generic Database file. This file contains a logical description of the design expressed both in terms of the hierarchy used when the design was first created and in terms of lower-level Xilinx primitives to which the hierarchy resolves. The file also contains all of the constraints applied to the design during design entry or entered in a UCF (User Constraints File). The NGD file is created by NGDBuild.
  
  
• NMC files - Macro library files. An NMC file contains the definition of a physical macro. When there are macro instances in the NGD design file, NMC files are used to define the macro instances. There is one NMC file for each type of macro in the design file.
  
  
• Guide NCD file - An optional input file generated from a previous MAP run. An NCD file contains a physical description of the design in terms of the components in the target Xilinx device. A guide NCD file is an output NCD file from a previous MAP run that is used as an input to guide a later MAP run.
  
  

  Note: Virtex and Spartan2 do not support guide files.

• MFP - Map Floorplanner File, which is generated by the Floorplanner, specified as an input file with the -fp option. The MFP file is essentially used as a guide file for mapping. To create a Map Floorplanner File, you must first have generated an NGD file and a mapped NCD file. When you have run MAP to generate an NCD file, you can open the mapped NCD file in the Floorplanner, modify the placement of components, and then generate an MFP file. You can then use the MFP file as an input file with the -fp map option. The MFP file is only created for the XC4000, Spartan/E/2, and Virtex architectures.
  
  
• MDF file - MAP Directive File. The MDF is an optional input file used for guided mapping. The MDF file describes how logic was decomposed when the guide design was mapped. MAP uses the hints in the MDF as a guide for logic decomposition in the guided mapping run.
  
  

Output Files

Output from MAP consists of the following files.

• NCD file - Native Circuit Description. A physical description of the design in terms of the components in the target Xilinx device. For a discussion of the output NCD file name and its location, see the “-o (Output File Name)” section.
  
  
• PCF (Physical Constraints) file - an ASCII text file containing the constraints specified during design entry expressed in terms of physical elements. The physical constraints in the PCF file are expressed in Xilinx's constraint language. This file is described in “The Physical Constraints (PCF) File” chapter.
  
  MAP either creates a PCF file if none exists or rewrites an existing file by overwriting the schematic-generated section of the file (between the statements SCHEMATIC START and SCHEMATIC END). For an existing physical constraints file, MAP also checks the user-generated section for syntax errors, and signals errors by halting the operation. If no errors are found in the user-generated section, the section is unchanged.
  
  
• NGM file - a binary design file containing all of the data in the input NGD file as well as information on the physical design produced by the mapping. The NGM file is used to correlate the back-annotated design netlist to the structure and naming of the source design.
  
  
• MRP (MAP report) file - a file containing information about the MAP command run. The MRP file lists any errors and warnings found in the design, lists design attributes specified, details on how the design was mapped (for example, the logic that was removed or added and how signals and symbols in the logical design were mapped into signals and components in the physical design). The file also supplies statistics about component usage in the mapped design. See “The MAP Report (MRP) File” section for more details.
  
  
• MDF (MAP Directive File) - a file describing how logic was decomposed when the design was mapped. In guided mapping, MAP uses the hints in the MDF as a guide for logic decomposition.
  
  

The MRP, MDF and NGM files produced by a MAP run all have the same name as the output file, with the appropriate extension. If the MRP, MDF or NGM files already exist, they are overwritten by the new files.