Tcl Fundamentals

This section provides some very basic information about the syntactic style of Xilinx Tcl commands. For more information about Tcl in general, please refer to Tcl documentation easily available on the internet, for example: http://www.tck.tk/doc , which is the website for the Tcl Developer Xchange.

In general, Tcl commands are procedural. Each Tcl command is a series of words, with the first word being the command name. For Xilinx Tcl commands, the command name is either a noun (e.g., project) or a verb (e.g., search). For commands that are nouns, the second word on the command line is the verb (e.g., project open). This second word is called the subcommand.

Subsequent words on the command line are additional parameters to the command. For Xilinx Tcl commands, required parameters are positional, which means they must always be specified in an exact order and follow the subcommand. Optional parameters follow the required parameters, can be specified in any order, and always have a flag that starts with “-“to indicate the parameter name; for example, -instance <instance-name>.

Tcl is case sensitive. Xilinx Tcl command names are always lower case. If the name is two words, the words are joined with an underscore (_). Even though Tcl is case sensitive, most design data (e.g., an instance name), property names, and property values are case insensitive. To make it less burdensome to type at the command prompt, unique prefixes are recognized when typing a subcommand, which means only typing the first few letters of a command name is all that is required for it to be recognized. Unique prefixes are also recognized for partition properties and property values.

The real power of Tcl is unleashed when it is used for nested commands and for scripting. The result of any command can be stored in a variable. Values are assigned to variables and properties with the set command. The set command takes two arguments. The first argument is the name of the variable and the second argument is the value. It is not necessary to declare Tcl variables before you use them. If one does not exist, it is created when the command is executed.

In Tcl, the dollar-sign ($) syntax is used to substitute a variable’s value for its name. For example, $foo in a Tcl command is replaced by the value of the variable foo.

The result of a command can also be substituted directly into another command. Tcl uses square brackets [ ] for these nested commands. Tcl interprets everything between square brackets [ ] as a command and substitutes the command result for the text within the square brackets [ ].

Tcl provides several ways to quote strings that contain spaces or other special characters and to manage substitution. Double quotes (“) allow some special characters ([ ] and $) for substitution. Curly braces { } perform no substitutions.

For very specific command line examples, please see the “Tcl Commands for General

Usage” and “Tcl Commands for Advanced Scripting” sections of this chapter.

Development System Reference Guide

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8.2i specifications

Xilinx 8.2i is a significant version of the Xilinx ISE (Integrated Software Environment) that emerged in the early 2000s, marking an important milestone in the world of FPGA (Field-Programmable Gate Array) development. This version introduced a slew of advanced features, technologies, and characteristics that made it an indispensable tool for engineers and developers in designing, simulating, and implementing digital circuits.

One of the standout features of Xilinx 8.2i is its enhanced design entry capabilities. This version supports multiple design entry methods, including schematic entry, VHDL, and Verilog HDL, giving engineers the flexibility to choose their preferred approach. The integrated environment provides user-friendly graphical interfaces, making it accessible for both novice and experienced users.

Xilinx 8.2i's synthesis tools have been improved to enable more efficient design compilation and optimization. The new algorithms used in this version facilitate faster synthesis times while reducing power consumption and improving performance. Furthermore, it features support for advanced FPGA architectures, which allows for the implementation of more complex designs with greater efficiency.

The implementation tools in Xilinx 8.2i include advanced place and route capabilities, utilizing state-of-the-art algorithms for optimized resource usage. These tools enable designers to make better use of FPGA resources, ensuring that designs fit within the constraints of the target device while maximizing performance.

Another key characteristic of Xilinx 8.2i is its extensive support for various Xilinx devices such as the Spartan, Virtex, and CoolRunner series. This compatibility ensures that developers can leverage the powerful features of these FPGA families, including high-speed transceivers and DSP slices.

Xilinx 8.2i also places a strong emphasis on simulation and verification. The version integrates with various simulation tools, allowing for thorough testing of the designs before implementation. This reduces the risk of errors and ensures that the final product meets specifications.

In addition, this version includes support for design constraints, enabling engineers to specify timing, area, and other critical design parameters. By accommodating constraints, Xilinx 8.2i helps in achieving reliable and efficient designs tailored to project needs.

In summary, Xilinx 8.2i is a robust software development tool that enhances the design process for FPGAs. Its comprehensive features, including multiple design entry options, advanced synthesis and implementation tools, extensive device support, and strong simulation capabilities, make it a valuable resource for engineers and developers striving for innovation in digital design.

Xilinx 8.2i manual Tcl Fundamentals

Models: 8.2i