Chapter 12: TRACE

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Setup Times

The external setup time is defined as the setup time of DATAPAD within IOB relative to CLKPAD within CLKIOB. When a guaranteed external setup time exists in the speed files for a particular DATAPAD and the CLKPAD pair and configuration, this number is used in timing reports. When no guaranteed external setup time exists in the speed files for a particular DATAPAD and CLKPAD pair, the external setup time is reported as the maximum path delay from DATAPAD to the IFD plus the maximum IFD setup time, less the minimum of maximum path delay(s) from the CLKPAD to the IFD.

Hold Times

The external hold time is defined as the hold time of DATAPAD within IOB relative to CLKPAD within CLKIOB. When a guaranteed external hold time exists in the speed files for a particular DATAPAD and the CLKPAD pair and configuration, this number is used in timing reports.

When no guaranteed external hold time exists in the speed files for a particular DATAPAD and CLKPAD pair, the external hold time is reported as the maximum path delay from CLKPAD to the IFD plus the maximum IFD hold time, less the minimum of maximum path delay(s) from the DATAPAD to the IFD.

Summary Report

The summary report includes the name of the design file being analyzed, the device speed and report level, followed by a statistical brief that includes the summary information and design statistics. The report also list statistics for each constraint in the PCF, including the number of timing errors for each constraint.

A summary report is produced when you do not enter an –e (error report) or –v (verbose report) option on the TRACE command line.

Two sample summary reports are shown below. The first sample shows the results without having a physical constraints file. The second sample shows the results when a physical constraints file is specified.

If no physical constraints file exists or if there are no timing constraints in the PCF, TRACE performs default path and net enumeration to provide timing analysis statistics. Default path enumeration includes all circuit paths to data and clock pins on sequential components and all data pins on primary outputs. Default net enumeration includes all nets.

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Xilinx 8.2i manual Setup Times, Hold Times
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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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