Altera Stratix GX Transceiver - Manual (Page 12)

1–4 Altera Corporation
Stratix GX Transceiver User Guide January 2005
Transceiver Block Architecture
Transmitter & Receiver Phase Compensation FIFO Buffer
The transmitter and receiver data path has a dedicated phase
compensation FIFO buffer that decouples phase variations between the
FPGA and transceiver clock domains. These FIFO buffers ensure a
consistent, reliable interface to the logic array and simplify system design
and timing analysis.
Byte Serializer/Deserializer
The byte serializer converts a 16- or 20-bit data bus into two 8- or 10-bit
data buses, respectively, at double the data rate. The byte serializer
converts an 8- or 10-bit data bus into 16- or 20-bit data buses, allowing
maximum throughput of the transceiver without burdening the FPGA
logic array.
The byte deserializer converts an 8- or 10-bit data bus into 16- or 20-bit
data buses, allowing maximum throughput of the transceiver without
burdening the FPGA logic array.
8B/10B Encoder/Decoder
8B/10B encoding/decoding is the backbone of many transceiver
protocols, and it is often used in proprietary implementations. The
gigabit transceiver block has dedicated circuitry to perform 8B/10B
encoding in the transmitter and decoding in the receiver. This coding
technique ensures sufficient data transitions and a DC balanced stream in
the data signal for successful data recovery at the receiver.
Word Aligner
The word aligner module contains a fully programmable pattern detector
to identify specific patterns within the incoming data stream. The pattern
detector includes recognition support /K28.5/ comma characters for
8B/10B encoded data and A1 or A2 frame alignment patterns for
scrambled signals. Additionally, you can specify a custom alignment
pattern in lieu of the /K28.5/ comma.
The word aligner in the gigabit transceiver block also creates words from
the incoming serial data stream by realigning the data based on identified
byte boundaries. The realignment function uses a barrel shifter and
works with the pattern detector. Additionally, the word aligner has a
manual data realignment mode that lets you control the data realignment
in user mode without consistent alignment characters.