Ports And Attributes; Chan_Bond_Mode; Enchansync; Chan_Bond_One_Shot - Xilinx RocketIO User Manual

Channel Bonding (Channel Alignment)
Table 2-19
Master and Slave applications.
Table 2-19: Master/Slave Channel Bonding Attribute Settings

Ports and Attributes

CHAN_BOND_MODE

An MGT can be designated as one of three types when used in a channel-bonding scheme. The type
is designated by CHAN_BOND_MODE, the three values of which are MASTER, SLAVE_1_HOP,
and SLAVE_2_HOPS. (A fourth mode, OFF, is used when channel bonding is not being performed.)
The Master always controls, for itself and for Slaves of either type, when channel bonding and clock
correction will occur.
Masters are always connected directly to a SLAVE_1_HOP, and indirectly to a SLAVE_2_HOPS
via daisy-chain through a SLAVE_1_HOP. This topology improves the timing characteristics of the
CHBONDO and CHBONDI buses.

ENCHANSYNC

ENCHANSYNC controls when channel bonding is enabled.
settings for Master and Slaves. To counter the possibility of a bit error causing a false channel
bonding sequence to occur, this port is usually de-asserted once a group of channels have been
successfully aligned.

CHAN_BOND_ONE_SHOT

As with ENCHANSYNC, many applications will require that the channels be aligned only once.
CHAN_BOND_ONE_SHOT = TRUE allows the Master to initiate a channel bonding only once.
This remains true even if more channel bonding sequences are received. (The channels may be
aligned again if RXRESET is asserted and then deasserted, and ENCHANSYNC is deasserted and
then reasserted.)
CHAN_BOND_ONE_SHOT may be set to FALSE when very few channel bonding sequences
appear in the data stream. (For Slave instantiations, this attribute should always be set to FALSE.
See
however, it is recommended that this attribute be set to TRUE in order to prevent the RX buffer from
over- or underflowing.

CHAN_BOND_SEQ_ * _ * ,

CHAN_BOND__SEQ_LEN,

CHAN_BOND_SEQ_2_USE

The channel bonding sequence (CBS) is similar in format to the clock correction sequence. The
CBS is set to the appropriate sequence for the primitives supporting channel bonding.
GT_CUSTOM is the only primitive allowing modification to the sequence. These sequences are
comprised of one or two sequences of length up to 4 bytes each, as set by
CHAN_BOND_SEQ_LEN and CHAN_BOND_SEQ_2_USE.
RocketIO™ Transceiver User Guide
UG024 (v2.3.2) June 24, 2004
shows different settings for CHAN_BOND_ONE_SHOT and ENCHANSYNC in
CHAN_BOND_ONE_SHOT
ENCHANSYNC
Table 2-19.) When the channel bonding sequence appears frequently in the data stream,
www.xilinx.com
1-800-255-7778
Master
TRUE or FALSE as desired
Dynamic control as desired
Table 2-19
R
Slave
FALSE
Tie High
shows the recommended
81