Xilinx 8.2i manual Bit Swapping in Prom Files, Enable Compression

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Chapter 16: PROMGen

R

–z (Enable Compression)

–zversion

The –z option enables compression for a Xilinx multi-bank PROM. All version will be compressed if one is not specified.

Bit Swapping in PROM Files

PROMGen produces a PROM file in which the bits within a byte are swapped compared to the bits in the input BIT file. Bit swapping (also called “bit mirroring”) reverses the bits within each byte, as shown in the following figure:

8

A

Original Data 1000

1010

Data in PROM File or HEX File 0101

0001

5

1

X8074

Figure 16-2: Bit Swapping

In a bitstream contained in a BIT file, the Least Significant Bit (LSB) is always on the left side of a byte. But when a PROM programmer or a microprocessor reads a data byte, it identifies the LSB on the right side of the byte. In order for the PROM programmer or microprocessor to read the bitstream correctly, the bits in each byte must first be swapped so they are read in the correct order.

In this release of the Xilinx Development System, the bits are swapped for all of the PROM formats: MCS, EXO, BIN, and TEK. For a HEX file output, bit swapping is on by default, but it can be turned off by entering a –b PROMGen option that is available only for HEX file format.

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Development System Reference Guide

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Xilinx 8.2i manual Bit Swapping in Prom Files, Enable Compression

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.