Use Modes - Rx Termination - Xilinx Virtex-6 FPGA User Manual

Chapter 4: Receiver
Table 4-2: RX AFE Attributes (Cont'd)
Attribute
TERMINATION_CTRL[4:0]
TERMINATION_OVRD
Use Modes – RX Termination
Table 4-3
Table 4-3: RX Termination Voltage and Attribute Mapping
RCV_TERM_GND
FALSE
FALSE
TRUE
TRUE
Note:
the north package power plane as outlined in
Table 4-4
shows the Use Mode 1 configuration.
Table 4-4: RX Termination Use Mode 1 Configuration
External
Use Mode AC
Voltage
Coupling
1 On
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186
Type
5-bit Binary Controls the internal termination calibration circuit. This is an
advance feature.
Boolean Selects whether the external 100 precision resistor connected to the
MGTRREF pin or an override value is used, as defined by
TERMINATION_CTRL[4:0]. This is an advance feature.
lists the possible settings for RCV_TERM_GND and RCV_TERM_VTTRX.
RCV_TERM_VTTRX
MGTAVTT_* refers to MGTAVTT_S of the south package power plane and MGTAVTT_N of
outlines the recommended settings for RX termination in Use Mode 1.
Term Internal AC Internal
Coupling Bias
GND On 800 mV
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Description
FALSE
TRUE
FALSE
TRUE
Figure 5-4, page
Max
Swing Suggested Protocols and Usage Notes
mV
DPP
1200 Protocol: PCIe
Attribute Settings:
AC_CAP_DIS = FALSE
RCV_TERM_GND = TRUE
RCV_TERM_VTTRX = FALSE
Virtex-6 FPGA GTX Transceivers User Guide
RX Termination Voltage
FLOAT
MGTAVTT_*
GND
RESERVED / NOT ALLOWED
277.
Figure 4-3
UG366 (v2.5) January 17, 2011