Stratix GX Transceivers
Parallel Loopback
The parallel loopback mode exercises the digital logic portion of the
transceiver data path. The analog portions are not use in the loopback
path. The received data is not retimed. Figure 2–22 shows the data path in
parallel loopback mode. This option is not dynamically switchable.
Reception of an external signal is not possible in this mode.
Figure 2–22. Data Path in Parallel Loopback Mode
BIST PRBS
Verifier
BIST
Incremental
Verifier
Word
Aligner
Deserializer
Channel
Aligner
Rate
Phase
Compensation
FIFO
Matcher
8B/10B
Decoder
Byte
Deserializer
Clock
Recovery
Unit
Phase
Compensation
FIFO
Byte
Serializer
Serializer
8B/10B
Encoder
BIST
Generator
Active Path
BIST PRBS
Generator
Non-Active Path
Reverse Serial Loopback
The reverse serial loopback exercises the analog portion of the
transceiver. This loopback mode is dynamically switchable through the
tx_srlpbkport on a channel by channel basis. Asserting
rxanalogresetin reverse serial loopback mode powers down the
receiver buffer and CRU, preventing data loopback. Figure 2–23 shows
the data path in reverse serial loopback mode.
Altera Corporation
June 2006
2–27
Stratix GX Device Handbook, Volume 1
ALTERA [ ALTERA CORPORATION ]
