Xilinx Virtex-5 RocketIO GTP

42 www.xilinx.com Virtex-5 RocketIO GTP Transceiver User Guide
UG196 (v1.3) May 25, 2007
Chapter 3: Simulation
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Ports and Attributes
The GTP_DUAL primitive has attributes intended only for simulation. Table 3-1 lists the
simulation-only attributes of the GTP_DUAL tile. The names of these attributes start with
SIM_.
There are no simulation-only ports.
Description
The behavior of the GTP_DUAL tile is modeled using a SmartModel. The SmartModel
allows the design containing GTP_DUAL tiles to be simulated in the following design
phases:
• Register Transfer Level (RTL)/Pre-Synthesis Simulation
• Post-Synthesis Simulation/Pre-NGDBuild Simulation
• Post-NGDBuild/Pre-Map Simulation
• Post-Map/Partial Timing Simulation
• Post-Place and Route/Timing Simulation
Limitations
The analog nature of some blocks inside the GTP_DUAL tile generates some restrictions
when simulated using an HDL simulator. Receiver detection and OOB/beacon signaling
are analog features of the GTP_DUAL tile that can only be modeled in a limited way with
an HDL simulator. The shared PMA PLL is another analog block in the GTP_DUAL that is
Table 3-1: GTP_DUAL Simulation-Only Attributes
Attribute Description
SIM_GTPRESET_SPEEDUP
This attribute shortens the time it takes to finish the GTPRESET sequence and
lock the shared PMA PLL during simulation.
TRUE: Shorten the GTPRESET cycle time (fast initialization is
approximately 300 ns). The value of SIM_PLL_PERDIV2 defines the PLL
frequency in this mode. Because SIM_PLL_PERDIV2 cannot be changed on
the fly during simulation, this mode cannot be used for multirate designs.
FALSE: The GTPRESET sequence is simulated with its original duration
(standard initialization is approximately 160 μs). This mode must be used
for multirate designs.
SIM_PLL_PERDIV2
This attribute specifies a 9-bit hex value equal to half the period of the PLL
clock frequency in picoseconds [ps]. For example, 400 ps (decimal) is equal to
0x190 (hexadecimal), which is the default value.
If SIM_PLL_PERDIV2 is not set correctly, poor locking behavior and incorrect
clock frequencies will occur in simulation.
SIM_RECEIVER_DETECT_PASS0
SIM_RECEIVER_DETECT_PASS1
This attribute is used to simulate the TXDETECTRX feature in each GTP
transceiver.
TRUE (default): Simulates an RX connection to the TX serial ports.
TXDETECTRX reports that an RX port is connected.
FALSE: Simulates a disconnected TX port. TXDETECTRX will report that
the RX port is not detected.