Xilinx 7 Series User Manual

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Xilinx 7 Series User Manual Manual pdf 20 page image

20 www.xilinx.com 7 Series FPGAs GTP Transceivers User GuideUG482 (v1.9) December 19, 2016Chapter 1: Transceiver and Tool OverviewImplementationFunctional DescriptionThis section provides the information needed to map 7 series GTP transceivers instantiated in adesign to device resources, including:• The location of the GTP transceiver Quads on the available device and package combinations.• The pad numbers of external signals associated with each GTP transceiver Quad.• How the GTPE2_CHANNEL primitive, the GTPE2_COMMON primitive, and clockingresources instantiated in a design are mapped to available locations with a user constraints file(UCF).It is a common practice to define the location of GTP transceiver Quads early in the design processto ensure correct usage of clock resources and to facilitate signal integrity analysis during boarddesign. The implementation flow facilitates this practice through the use of location constraints inthe UCF.This section describes how to instantiate GTP transceiver clocking components.The position of each GTP transceiver channel and common primitive is specified by an XYcoordinate system that describes the column number and the relative position within that column.For a given device/package combination, the transceiver with the coordinates X0Y0 is alwayslocated at the lowest position of the lowest available bank.There are two ways to create a UCF for designs that utilize the GTP transceiver. The preferredmethod is to use the 7 Series FPGAs Transceivers Wizard. The Wizard automatically generates UCFtemplates that configure the transceivers and contain placeholders for GTP transceiver placementinformation. The UCFs generated by the Wizard can then be edited to customize operatingparameters and placement information for the application.The second approach is to create the UCF by hand. When using this approach, the designer mustenter both configuration attributes that control transceiver operation as well as tile locationparameters. Care must be taken to ensure that all of the parameters needed to configure the GTPtransceiver are correctly entered.If a design requires the use of any of the GTP channels in a given GTP Quad, a GTPE2_COMMONprimitive must be instantiated as shown in Figure 1-5. At a minimum, at least oneGTPE2_CHANNEL must also be instantiated. Figure 1-5 shows four GTPE2_CHANNELprimitives instantiated.Send Feedback