Altera Corporation
2–151
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Transceiver Architecture Overview
The Stratix II GX device has dedicated circuits to support the PCI Express
protocol, including the following:
■
8B/10B encoder and decoder
■
Rate matcher, which supports a multi-crystal environment up to
±300 PPM (600 PPM total) clock difference
■
PIPE interface (Physical Interface for PCI Express)
■
Receiver detection
■
Beacon transmit capability
■
Loopback
■
Inversion
■
Disparity control
The PHY state machines, except for rate matching, are not included in the
transceiver. Those state machines can be created in the PLD logic. This
mode of operation is called the PIPE mode.The PIPE mode has a separate
reset sequence. Refer to
“Reset Sequence for PIPE Mode” on page 2–218
for more information.
f
The equalizer DC gain value in the MegaWizard Plug-In Manager for
PIPE mode is set to a default value of 1. If the equalizer DC gain is
controlled by the ALT2GXB_RECONFIG controller, the
rx_eqdcgain
input to the ALT2GXB_RECONFIG controller should be tied to “01” to
be PCI E-compliant. Refer to the
ALT2GXB Megafunction User Guide
chapter in volume 2 of the
Stratix II GX Device Handbook
for more
information.
Synchronization
In PIPE mode, the synchronization automatically occurs when the
receiver receives 4 good /K28.5/ commas and 16 good code groups.
Synchronization can be accomplished through the reception of four good
PCI Express training sequences (TS1 or TS2) or four fast training
sequences.
Figure 2–115
shows a state diagram of the PCI-E
synchronization.