R

BitGen Options

The rawbits file consists of ASCII ones and zeros representing the data in the bitstream file. If you are using a microprocessor to configure a single FPGA, you can include the rawbits file in the source code as a text file to represent the configuration data. The sequence of characters in the rawbits file is the same as the sequence of bits written into the FPGA.

–bd (Update Block Rams)

–bdfile_name

The –bd option updates the bitstream with the block ram content from the specified ELF or MEM file. See Chapter 24, “Data2MEM” for more information.

–d (Do Not Run DRC)

Do not run DRC (design rule check). Without the –d option, BitGen runs a DRC and saves the DRC results in two output files: the BitGen report file (file_name.bgn) and the DRC file (file_name.drc). If you enter the –d option, no DRC information appears in the report file and no DRC file is produced.

Running DRC before a bitstream is produced detects any errors that could cause the FPGA to malfunction. If DRC does not detect any errors, BitGen produces a bitstream file (unless you use the –j option described in “–j (No BIT File)”).

–f (Execute Commands File)

–fcommand_file

The –f option executes the command line arguments in the specified command_file. For more information on the –f option, see “–f (Execute Commands File)” in Chapter 1.

–g (Set Configuration)

The –g option specifies the startup timing and other bitstream options for Xilinx FPGAs. The debug bitstream can only be used for master and slave serial configurations. It is not valid for Boundary Scan or Slave Parallel/Select MAP. The settings for the –g option depend on the architecture of the design. These settings are described in the following section:

–g (Set Configuration—Virtex/-E/-II/-II Pro/-4 and Spartan-II/-IIE/-3/-3E)

The –g option has sub-options that represent settings you use to set the configuration for a Virtex/-E/-II/-II Pro or Spartan-II/-IIE/3 design. These options have the following syntax:

bitgen –goption:setting design.ncd design.bit design.pcf

For example, to enable Readback, use the following syntax:

bitgen –g Readback

The following sections describe the options and settings for the –g option. Each –g option is listed with supported architectures, settings, and defaults.

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.
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