EP4CE30F29C7N Datasheet, PDF (352/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

1–72
Chapter 1: Cyclone IV Transceivers Architecture
Transceiver Functional Modes
■ Channel alignment is acquired if three additional aligned ||A|| columns are
observed at the output of the deskew FIFOs of the four channels after alignment of
the first ||A|| column.
■ Channel alignment is indicated by the assertion of rx_channelaligned signal.
■ After acquiring channel alignment, if four misaligned ||A|| columns are seen at
the output of the deskew FIFOs in all four channels with no aligned ||A||
columns in between, the rx_channelaligned signal is deasserted, indicating loss of
channel alignment.
Figure 1–65 shows lane skew at the receiver input and how the deskew FIFO uses the
/A/ code group to align the channels.
Figure 1–65. Deskew FIFO–Lane Skew at the Receiver Input
Lane 0 K
K
R
A
K
R
R
K
K
R
K
R
Lane 1 K
K
R
A
K
R
R
K
K
R
K
R
Lane 2 K
K
R
A
K
R
R
K
K
R
K
R
Lane 3 K
K
R
A
K
R
R
K
K
R
K
R
Lanes skew at
receiver input
Lane 0 K
K
R
A
K
R
R
K
K
R
K
R
Lane 1 K
K
R
A
K
R
R
K
K
R
K
R
Lanes are deskewed by lining
up the “Align”/A/ code groups
Lane 2 K
K
R
A
K
R
R
K
K
R
K
R
Lane 3 K
K
R
A
K
R
R
K
K
R
K
R
/A/ column
Lane Synchronization
In XAUI mode, the word aligner is configured in automatic synchronization state
machine mode that is compliant to the PCS synchronization state diagram specified in
clause 48 of the IEEE P802.3ae specification. Table 1–23 lists the synchronization state
machine parameters that implements the lane synchronization in XAUI mode.
Table 1–23. Synchronization State Machine Parameters ⁽¹⁾
Parameter
Number of valid synchronization (/K28.5/) code groups received to achieve
synchronization
Number of erroneous code groups received to lose synchronization
Number of continuous good code groups received to reduce the error count by
one
Note to Table 1–23:
(1) The word aligner supports 7-bit and 10-bit pattern lengths in XAUI mode.
Value
4
4
4
Cyclone IV Device Handbook,
Volume 2
October 2013 Altera Corporation