Figure 2–18. Word Aligner in XAUI Mode
Word Aligner
Synchronization
State Machines
GigE
Mode
XAUI
Mode
In the XAUI and GIGE modes, the word alignment is controlled by a state
machine that adheres to the IEEE 802.3ae standard for XAUI and the
IEEE 802.3 standard for GIGE. The alignment pattern is predefined to be
a /K28.5/code group.
The XAUI mode is available only for the XAUI protocol, and the GIGE
mode is available only for the GIGE protocol.
Channel Aligner
The channel aligner is available only in XAUI mode and bonds all four
channels within a transceiver. The channel aligner adheres to the
IEEE 802.3ae, clause 48 specification for channel bonding.
The channel aligner is a 16-word deep FIFO buffer with a state machine
overlooking the channel bonding process. The state machine looks for an
/A/(/K28.3/) in each channel and aligns all the /A/s in the transceiver.
When four columns of /A/(denoted by //A//) are detected, the
rx_channelalignport goes high, signifying that all the channels in the
transceiver have been bonded. The reception of four consecutive
misaligned /A/s restarts the channel alignment sequence and de-asserts
rx_channelalign.
Figure 2–19 shows misaligned channels before the channel aligner and
the channel alignment after the channel aligner.
2–22
Stratix GX Device Handbook, Volume 1
Altera Corporation
June 2006
ALTERA [ ALTERA CORPORATION ]
