Xilinx Virtex-6 FPGA User Manual page 107

Table 2-4: GTX Clocking Ports (Cont'd)
Port
RXPLLREFSELDY[2:0]
SOUTHREFCLKRX[1:0]
SOUTHREFCLKTX[1:0]
TXPLLREFSELDY[2:0]
Table 2-5
Table 2-5: GTX Clocking Attributes
Attribute
PMA_CAS_CLK_EN
SIM_RXREFCLK_SOURCE[2:0]
SIM_TXREFCLK_SOURCE[2:0]
www.BDTIC.com/XILINX
Virtex-6 FPGA GTX Transceivers User Guide
UG366 (v2.5) January 17, 2011
Dir Clock Domain
In Async Receiver PLL reference clock dynamic selection. Set to 000 when
one reference clock is used.
When multiple reference clocks are connected,
RXPLLREFSELDY provides dynamic selection as follows:
000: MGTREFCLKRX[0] selected
001: MGTREFCLKRX[1] selected
010: NORTHREFCLKRX[0] selected
011: NORTHREFCLKRX[1] selected
100: SOUTHREFCLKRX[0] selected
101: SOUTHREFCLKRX[1] selected
110: No connect
111: GREFCLKRX or PERFCLKRX selected (only one of these
can be used at a time)
In Clock South-bound clocks from the Quad above.
In Clock South-bound clocks from the Quad above.
In Async Transmitter PLL reference clock dynamic selection. Set to 000
when one reference clock is used.
When multiple reference clocks are connected,
TXPLLREFSELDY provides dynamic selection as follows:
000: MGTREFCLKTX[0] selected
001: MGTREFCLKTX[1] selected
010: NORTHREFCLKTX[0] selected
011: NORTHREFCLKTX[1] selected
100: SOUTHREFCLKTX[0] selected
101: SOUTHREFCLKTX[1] selected
110: CAS_CLK (Internal clock generated from the RX PLL)
111: GREFCLKTX or PERFCLKTX selected (only one of these
can be used at a time)
defines the GTX clocking attributes.
Type
Boolean This attribute is the enable for CAS_CLK from the receiver
forwarded to the transmitter PLL.
TRUE: Enables CAS_CLK. TXPLLREFSELDY[2:0] is unused in
this case.
FALSE: Disables CAS_CLK.
3-bit Binary Simulation control for GTX reference clock selection. This attribute
must contain the same binary value as the RXPLLREFSELDY port.
3-bit Binary Simulation control for the GTX reference clock selection. This
attribute is set to the same binary value as the TXPLLREFSELDY
port.
www.xilinx.com
Reference Clock Selection
Description
Description
107