Altera Cyclone V Device Handbook page 326

CV-53001
2013.05.06
Word Aligner in Automatic Synchronization State Machine Mode
In automatic synchronization state machine mode, a programmable state machine determines the moment
that the word aligner has either achieved synchronization or lost synchronization.
You can configure the state machine to provide hysteresis control during link synchronization and throughout
normal link operation. Depending on your protocol configurations, the state machine parameters are
automatically configured so they are compliant with the synchronization state machine in the respective
protocol specification.
Table 1-20: Programmable Parameters for the Word Aligner in Synchronization State Machine Mode
Number of valid synchronization code groups or ordered sets 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
Table 1-21: Word Aligner Operation in Automatic Synchronization State Machine Mode
PCS Mode
Single Width
Word Aligner in Automatic Synchronization State Machine Mode with a 10-Bit PMA-PCS Interface
Configuration
Protocols such as PCIe require the receiver PCS logic to implement a synchronization state machine to
provide hysteresis during link synchronization. Each of these protocols defines a specific number of
Transceiver Architecture in Cyclone V Devices
Send Feedback
Word Aligner in Automatic Synchronization State Machine Mode
Parameter
PMA PCS Interface
Width
10 bits 1. After the rx_digitalreset signal deasserts, the word
aligner starts looking for the predefined word alignment pattern,
or its complement, in the received data stream and automatically
aligns to the new word boundary.
2. Synchronization is achieved only after the word aligner receives
the programmed number of valid synchronization code groups
in the same word boundary and is indicated with the assertion
of the rx_syncstatus signal.
3. After assertion and achieving synchronization, the rx_
syncstatus signal remains asserted until the word aligner
loses synchronization.
4. Loss of synchronization occurs when the word aligner receives
the programmed number of erroneous code groups without
receiving the intermediate good code groups and is indicated
with the deassertion of the rx_syncstatus signal.
5. The word aligner may achieve synchronization again after
receiving a new programmed number of valid synchronization
code groups in the same word boundary.
1 256
1 64
1 256
Word Alignment Operation
1-39
Values
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