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Chapter 5: Constraining the Core

Timing Ignore Constraints

If Source core static configuration signals are driven statically from a register, apply the timing ignore attributes (TIG) to the static configuration signals to create proper timing ignore paths. If these are driven statically from a wrapper file, then the TIG is not needed.

In the example UCF, these constraints are commented out. Uncomment these constraints in your design.

NET "SrcAFThresAssert(*)" TIG;

NET "SrcAFThresNegate(*)" TIG;

NET "DataMaxT(*)”;

NET "AlphaData(*)”;

NET "SrcBurstLen(*)”;

NET "NumDip2Errors(*)”;

NET "NumDip2Matches(*)”;

User Constraints

In certain cases, you may need to add additional constraints to cover other logic implemented in your design. While the UCF file provided with the core is designed to completely constrain the Xilinx SPI-4.2 Lite core, it may not adequately constrain user- implemented logic interfaced to the core.

Constraints Migration

The example UCF file provided with the core must be modified to migrate the core to a different area or target device.

The examples in this section indicate the changes necessary to migrate the Sink and Source cores to user-defined locations on a XC4VLX40-FF1148 Virtex-4 part by modifying the example UCF that targets XC4LX25-FF1148. The static alignment example shows the migration of the Sink and Source cores to the south-west region of the part (banks 11 and 8).

New Target Region or Device Package

When selecting a new target region or device package, first verify that the new region has enough resources required for the generated core. Resources that need to be taken into considerations are:

Block RAMs

I/O Pins (in targeted I/O banks)

Logic cells

Clocking resources: DCM, regional and global buffers

Below are some typical region selections within a device.

Source Core: One clock region on the same side of the device, east or west.

Sink Core (static): One clock region on the same side of the device.

The east side is the side of the device with even numbered I/O banks: 6, 8, 10, and so on.

The west side is the side of the device with odd numbered I/O banks: 5, 7, 9, and so on.

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SPI-4.2 Lite v4.3 User Guide

 

 

UG181 June 27, 2008

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Xilinx UG181 manual User Constraints, Constraints Migration, New Target Region or Device Package

UG181 specifications

Xilinx UG181 refers to the User Guide for the Xilinx 7 Series FPGAs, which offers a comprehensive overview of the architecture, capabilities, and features of these powerful field-programmable gate arrays (FPGAs). Designed to cater to a wide range of applications, Xilinx 7 Series FPGAs are widely adopted in industries such as telecommunications, automotive, aerospace, and consumer electronics.

One of the main features of the Xilinx 7 Series FPGAs is their use of advanced 28nm technology, which enables them to achieve high performance while maintaining low power consumption. This fine process technology not only ensures better power efficiency but also allows for increased logic density. The 7 Series includes several families, such as Artix-7, Kintex-7, and Virtex-7, each tailored for specific application demands ranging from cost-sensitive solutions to high-performance data processing.

Xilinx 7 Series FPGAs also incorporate a rich set of programmable logic resources. This includes Look-Up Tables (LUTs), Flip-Flops, and Digital Signal Processing (DSP) slices that have been optimized for various arithmetic functions. With several thousands of logic cells available, designers can implement complex algorithms and systems directly in hardware for improved performance over traditional software solutions.

In addition to their logic capabilities, Xilinx 7 Series FPGAs feature an array of high-speed serial communication interfaces. These include support for technologies like PCI Express, Gigabit Ethernet, and Serial RapidIO, which facilitate efficient data transfer and integration into enterprise-level systems. The presence of high-speed transceivers also makes them ideal for applications that require fast data handling like video processing or high-frequency trading.

Furthermore, these FPGAs offer extensive memory options, including support for a wide range of external memory interfaces. This versatility allows for the integration of high-bandwidth memory solutions, which is essential for performance-intensive applications. With the introduction of the Memory Controller IP, users can easily connect various memory types, ensuring flexibility in system design.

Finally, Xilinx has made significant strides in development tools for 7 Series FPGAs, providing a robust ecosystem for design engineers. With design suites such as Vivado and SDK, users benefit from a comprehensive platform for deciding, simulating, and implementing designs efficiently. The combination of advanced hardware capabilities and powerful software tools solidifies the position of Xilinx 7 Series FPGAs as a preferred choice for custom digital hardware design across various industries.