Virtex-4 RocketIO MGT User Guide www.xilinx.com 179UG076 (v4.1) November 2, 2008RChapter 7Simulation and ImplementationModel ConsiderationsThe RocketIO™ MGT SWIFT Model simulates the PLL in the same fashion as in theVirtex®-II Pro device. To save simulation time, the PLL locks much faster than inhardware.The COMBUSIN/COMBUSOUT ports between each pair of MGTs sharing a tile must beconnected. Table 7-1 shows the required setting for GT11_MODE. The RocketIO wizardcan be used to automatically set GT11_MODE, as well as instantiate and connect a secondMGT when necessary.Simulation ModelsSmartModelsSmartModels are encrypted versions of the actual HDL code. These models allow the userto simulate the actual functionality of the design without having access to the code itself.The SmartModel must be installed in a SmartModel-capable simulator before it can beused. This can be accomplished using the same compxlib utility that installs other Xilinxsimulation libraries, such as UNISIMS and SIMPRIMS.Table 7-1: GT11_MODE DescriptionValue DescriptionSINGLESetting if only one MGT in the tile is used. (Other MGT to be set toDONT_CARE). It is suggested that the bottom MGT in a tile be used forthis application.NOTE: It is recommended that either the A or B setting be used. TheSINGLE setting is not recommended.A Setting when both MGTs in a tile are used.(This is the top MGT) = LOC = Xx Yeven+1B Setting when both MGTs in a tile are used.(This is the bottom MGT) = LOC = X x YevenDONT_CARE Setting when the MGT is not used.
