During this run, XST creates the following files.

♦watchvhd.ngc: an NGC file ready for the implementation tools

♦design.srp: the xst script log file

3.To save XST messages in a different log file (for example, watchver.log), run the following command:

xst -ifn design.xst -ofn watchver.log

To improve the readability of the design.xst file, especially if you use many options to run synthesis, place each option with its value on a separate line. Observe the following rules:

•The first line contains only the run command without any options.

•There are no blank lines in the middle of the command.

•Each line (except the first one) begins with a dash (–).

For the previous command example, the design.xst file should look like the following:

run

-ifn watchver.prj -ifmt mixed

-top stopwatch -ofn watchver.ngc -ofmt NGC

-p xcv50-bg256-6 -opt_mode Speed -opt_level 1

Synthesizing Mixed Designs Using Command Line Mode

This example shows the synthesis of a hierarchical mixed VHDL and Verilog design for a Virtex FPGA using command line mode.

1.Create a new directory named vhdl_verilog.

2.Copy the following files from the ISEexamples\watchvhd directory of the ISE installation directory to the newly-created vhdl_verilog directory.

♦stopwatch.vhd

♦statmach.vhd

♦decode.vhd

♦cnt60.vhd

♦smallcntr.vhd

♦tenths.vhd

3.Copy the hex2led.v file from the ISEexamples\watchver directory of the ISE installation directory to the newly created vhdl_verilog directory.

To synthesize the design, which is now represented by six VHDL files and one Verilog file, create a project. To create a project file, place a list of VHDL files preceded by keyword vhdl, and a list of Verilog files preceded by keyword verilog in a separate file. The order of the files is not important. XST recognizes the hierarchy and compiles Hardware Description Language (HDL) files in the correct order.

Synthesizing Mixed Designs Using Command Line Mode (Example)

1.Open a new file called watchver.prj.

2.Enter the names of the files into this file in any order and save it: vhdl work decode.vhd

vhdl work statmach.vhd vhdl work stopwatch.vhd vhdl work cnt60.vhd vhdl work smallcntr.vhd vhdl work tenths.vhd verilog work hex2led.v

3.To synthesize the design, execute the following command from the XST shell or a script file:

run -ifn watchver.prj -ifmt mixed -top stopwatch -ofn watchver.ngc -ofmt NGC -p xcv50-bg256-6 -opt_mode Speed -opt_level 1

You must specify the top-level design block with the -top command line option.

and check its performance independently of the other blocks, you can specify it as the top level module to synthesize on the command line by using the -top option. For more information, see Table 5-1, page 318.

run -ifn watchver.prj -ifmt mixed -top hex2led -ofn watchver.ngc -ofmt NGC -p xcv50-bg256-6 -opt_mode Speed -opt_level 1

Running XST in Script Mode (Mixed Language)

It can be tedious to enter XST commands directly into the XST shell, especially when you have to specify several options and execute the same command several times. You can run XST in a script mode as follows.

1.Open a new file called stopwatch.xst in the current directory. Put the previously executed XST shell command into this file and save it.

run -ifn watchver.prj -ifmt mixed -top stopwatch -ofn watchver.ngc -ofmt NGC -p xcv50-bg256-6 -opt_mode Speed -opt_level 1

2.From the tcsh or other shell, enter the following command to begin synthesis. xst -ifn stopwatch.xst

During this run, XST creates the following files:

♦watchver.ngc: an NGC file ready for the implementation tools

♦xst.srp: the xst script log file

3.If you want to save XST messages in a different log file for example, watchver.log, execute the following command.

xst -ifn stopwatch.xst -ofn watchver.log

To improve the readability of the stopwatch.xst file, especially if you use many options to run synthesis, place each option with its value on a separate line. Observe the following rules:

•The first line contains only the run command without any options.

•There are no blank lines in the middle of the command.

•Each line (except the first one) begins with a dash (–).

10.1

For the previous command example, the stopwatch.xst file should look like the following:

run

-ifn watchver.prj -ifmt mixed

-ofn watchver.ngc -ofmt NGC

-p xcv50-bg256-6 -opt_mode Speed -opt_level 1