Altera Corporation
2–199
October 2007
Stratix II GX Device Handbook, Volume 2
Stratix II GX Transceiver Architecture Overview
1
Stratix II GX transceivers do not have built-in support for other
PCS functions; for example, clock frequency compensation
between upstream transmitter clock and local receiver clock
(rate matcher), pseudo-random idle sequence generation, and
lane alignment in 4× mode. Depending on your system
requirements, you must implement these functions in the logic
array or external circuits.
Synchronization State Machine
In Serial RapidIO mode, the ALT2GXB MegaWizard Plug-In Manager
defaults the word alignment pattern to K28.5. The word aligner has a
Synchronization State Machine that handles the receiver lane
synchronization.
The ALT2GXB MegaWizard Plug-In Manager automatically defaults the
synchronization state machine to indicate synchronization when the
receiver receives 127 K28.5 (10'b0101111100 or 10'b1010000011)
synchronization code groups without receiving an intermediate invalid
code group. Once synchronized, the state machine indicates loss of
synchronization when it detects three invalid code groups separated by
less than 255 valid code groups or when it is reset.
Receiver synchronization is indicated on the
rx_syncstatus
port of
each channel. A high on the
rx_syncstatus
port indicates that the lane
is synchronized and a low indicates that it has fallen out of
synchronization.
Table 2–46
lists the ALT2GXB synchronization state machine parameters
when configured in Serial RapidIO mode.
Table 2–46. Synchronization State Machine Parameters in Serial RapidIO
Mode
Parameters
Number
Number of valid K28.5 code groups received to achieve
synchronization.
127
Number of errors received to lose synchronization.
3
Number of continuous good code groups received to reduce the
error count by one.
255