Xilinx 8.2i manual Ol Overall Effort Level, Olstdmedhigh

Chapter 7: MAP

R

•If you do not specify an output file name with the –o option, the output file has the same name as the input file, with a .ncd extension. The file is placed in the input file’s directory

•If you specify an output file name with instead of /home/designs/cpu_dec.ncd) directory.

no path specifier (for example, cpu_dec.ncd , the NCD file is placed in the current working

•If you specify an output file name with a full path specifier (for example, /home/designs/cpu_dec.ncd), the output file is placed in the specified directory.

If the output file already exists, it is overwritten with the new NCD file. You do not receive a warning when the file is overwritten.

Note: However, signals connected to pads or to the outputs of BUFTs, flip-flops, latches, and

RAMS are preserved for back-annotation.

–ol (Overall Effort Level)

–ol[stdmedhigh]

The –ol option is available when running timing-driven packing and placement with the – timing option. The –ol option sets the overall MAP effort level. The effort level specifies the level of effort MAP uses to pack the design.

Of the three effort_level values, use std for low effort level (fastest runtime at expense of QOR), use med for medium effort level (balance of runtime and QOR), use high for high effort level (best QOR with increased runtime).

The default effort level in MAP is high. Following is command line syntax for using the

–ol option, set to std:

map –timing –ol std design.ncd output.ncd design.pcf

Note: The –ol option is ignored if the –timing option is not set.

–p (Part Number)

–ppart

Specifies the Xilinx part number for the device. The syntax for the –p option is described in “–p (Part Number)” in Chapter 1.

If you do not specify a part number using the –p option, MAP selects the part specified in the input NGD file. If the information in the input NGD file does not specify a complete device and package, you must enter a device and package specification using the –p option. MAP supplies a default speed value, if necessary.

The architecture you specify with the –p option must match the architecture specified within the input NGD file. You may have chosen this architecture when you ran NGDBuild or during an earlier step in the design entry process (for example, you may have specified the architecture as an attribute within a schematic, or specified it as an option to a netlist reader). If the architecture does not match, you have to run NGDBuild again and specify the desired architecture.

You can only enter a part number or device name from a device library you have installed on your system. For example, if you have not installed the 4006E device library, you cannot create a design using the 4006E–PC84 part.

138 www.xilinx.com Development System Reference Guide