R

TRACE Reports

The following command verifies the timing characteristics for the design named design1.ncd using the timing constraints contained in the timing file .pcf, and generates an error report. The error report lists the three worst errors for each constraint in timing .pcf. The error report file is called design1.twr.

trce –e 3 design1.ncd timing.pcf

TRACE Reports

Default output from TRACE is an ASCII formatted timing report file that provides information on how well the timing constraints for the design are met. The file is written into your working directory and has a .twr extension. The default name for the file is the root name of the input NCD file. You can designate a different root name for the file, but it must have a .twr extension. The .twr extension is assumed if not specified.

The timing report lists statistics on the design, any detected timing errors, and a number of warning conditions.

Timing errors show absolute or relative timing constraint violations, and include the following:

•Path delay errors—where the path delay exceeds the MAXIMUM DELAY constraint for a path.

•Net delay errors—where a net connection delay exceeds the MAXIMUM DELAY constraint for the net.

•Offset errors—where either the delay offset between an external clock and its associated data-in pin is insufficient to meet the timing requirements of the internal logic or the delay offset between an external clock and its associated data-out pin exceeds the timing requirements of the external logic.

•Net skew errors—where skew between net connections exceeds the maximum skew constraint for the net.

To correct timing errors, you may need to modify your design, modify the constraints, or rerun PAR.

Warnings point out potential problems, such as circuit cycles or a constraint that does not apply to any paths.

Three types of reports are available: summary, error, and verbose. You determine the report type by entering the corresponding TRACE command line option, or by selecting the type of report when using the Timing Analyzer GUI tool (see “TRACE Options”). Each type of report is described in “Reporting with TRACE.”

In addition to the ASCII formatted timing report (TWR) file, you can generate an XML timing report (TWX) file with the –xml option. The XML report is not formatted and can only be viewed with the Timing Analyzer GUI tool.

Note: The Constraints Interaction report (TSI), also referred to as the Timing Specification

Interaction report, is no longer available.

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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.
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