Pr Pack Registers in I/O, No Register Ordering

MAP Options

–pr (Pack Registers in I/O)

–pr {i o b}

By default (without the –pr option), MAP only places flip-flops or latches within an I/O cell if your design entry method specifies that these components are to be placed within I/O cells. For example, if you create a schematic using IFDX (Input D Flip-Flop) or OFDX (Output D Flip-Flop) design elements, the physical components corresponding to these design elements must be placed in I/O cells. The –pr option specifies that flip-flops or latches may be packed into input registers (i selection), output registers (o selection), or both (b selection) even if the components have not been specified in this way.

–r (No Register Ordering)

By default (without the –r option), MAP looks at the register bit names for similarities and tries to map register bits in an ordered manner (called register ordering). If you specify the -r option, register bit names are ignored when registers are mapped, and the bits are not mapped in any special order. For a description of register ordering, see “Register Ordering”.

–register_duplication (Duplicate Registers)

The –register_duplication option is only available when running timing-driven packing and placement with the –timing option. The –register_duplication option duplicates registers to improve timing when running timing-driven packing. See “–timing (Timing- Driven Packing and Placement).”

–retiming (Register Retiming During Global Optimization)

–retiming onoff

When this option is on, registers are moved forward or backwards through the logic to balance out the delays in a timing path to increase the overall clock frequency. The overall number of registers may be altered due to the processing. This option is available for Virtex-4 designs. By default, this option is off.

Note: This option is available only when “–global_opt (Global Optimization)” is used.

–t (Start Placer Cost Table)

–tplacer_cost_table

The –t option is only available when running timing-driven packing and placement with the –timing option. The –t option specifies the cost table at which the placer starts (placer cost tables are described in Chapter 9, “PAR”). The placer_cost_table range is 1–100. The default is 1.

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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 Pr Pack Registers in I/O, No Register Ordering, Start Placer Cost Table

Models: 8.2i