Xilinx 7 Series User Manual page 201

Table 4-40: RX Channel Bonding Attributes (Cont'd)
Attribute
FTS_DESKEW_SEQ_ENABLE
FTS_LANE_DESKEW_CFG
FTS_LANE_DESKEW_EN
PCS_PCIE_EN
7 Series FPGAs GTP Transceivers User Guide
UG482 (v1.9) December 19, 2016
Type
4-bit Binary Enable mask for FTS_LANE_DESKEW_CFG.
FTS_DESKEW_SEQ_ENABLE[0] is for
FTS_LANE_DESKEW_CFG[0]
FTS_DESKEW_SEQ_ENABLE[1] is for
FTS_LANE_DESKEW_CFG[1]
FTS_DESKEW_SEQ_ENABLE[2] is for
FTS_LANE_DESKEW_CFG[2]
FTS_DESKEW_SEQ_ENABLE[3] is for
FTS_LANE_DESKEW_CFG[3]
The default value is 1111.
4-bit Binary • Bit 3: This bit is set to 1'b1 on a slave to freeze the alignment to
prevent spurious misalignments or modified alignments that can occur
following slip-4, snap-4, or clock correction when good channel
alignment is still maintained. This bit is set to 1'b0 on a slave to
unfreeze the alignment.
• Bit 2: Specifies whether a "master" channel doing FTS lane deskew
that just reached the end of an FTS OS in its lookahead control logic
inhibits its own generation of clock correction commands for a brief
time. The purpose is to prevent clock correction commands from
interfering with operation of the slave's slip-4 and snap-4 logic. The
logic guarantees that clock correction can still occur if a full SKP OS
is present.
• Bit 1: Specifies whether a "slave" channel doing FTS lane deskew is
permitted (1'b1) or inhibited (1'b0) from performing an immediate
backward alignment adjustment by four bytes (slip-4) if the slave is
found to have reached the SKP OS following FTS before the master
has.
• Bit 0: Specifies whether a "slave" channel doing FTS lane deskew is
permitted (1'b1) or inhibited (1'b0) from performing an immediate
forward alignment adjustment by four bytes (snap-4) if the master is
found to have reached the SKP OS following FTS before the slave has.
String This attribute is set to TRUE to enable channel bonding logic for FTS
lane deskew. FTS lane deskew is separate from the standard algorithm
using channel bonding sequences 1 and 2, and it operates in parallel with
the standard algorithm. FTS lane deskew operates only in two-byte mode.
String This attribute is set to TRUE when the GTP transceiver is used for PCI
Express and set to FALSE for all other protocols. The channel bonding
function requires this attribute together with TXCHARDISPMODE and
TXCHARDISPVAL to support PIPE encode and FTS lane deskew. It also
works together with TXELECIDLE to match a shorter sequence from
reusing prior channel bonding information after the GTP transceiver
returns from electrical idle.
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RX Channel Bonding
Description
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