1–4
Altera Corporation
Stratix II GX Device Handbook, Volume 2
October 2007
Receiver Channel Overview
Serializer
The serializer converts the incoming lower speed parallel signal from the
transceiver’s physical coding sublayer (PCS) to a high-speed serial signal
on the transmit side. The serializer supports a variety of conversion
factors, ensuring implementation flexibility. The serializer supports an
8- or 10-bit serialization factor in single-width mode and a 16- or 20-bit
serialization factor in double-width mode. The serializer block also
performs clock synthesis on the slow-speed clock for the parallel
transmitter logic in the transceiver and PLD.
Transmitter Differential Output Buffers
The gigabit transceiver block differential output buffers support the 1.5-V
PCML and 1.2-V PCML I/O standards and have a variety of features that
improve system signal integrity. Programmable pre-emphasis helps
compensate for high frequency losses. A variety of programmable
voltage output differential (V
OD
) settings allow noise margin tuning
capabilities. Additionally, on-chip termination (OCT) provides the
appropriate transmitter buffer termination for 100-, 120-, or 150-
Ω
transmission lines. The transmitter buffer circuit also contains a
receiver-detect circuit for use with the PCI Express (PIPE) protocol to
detect if a receiver is connected. The buffer can be tri-stated to reduce
electromagnetic interference (EMI) and power consumption when not in
use. In PIPE mode, the tri-state feature generates Electrical Idle.
Receiver
Channel
Overview
This section provides a brief description about the various components
within the receiver block. The modules originate from the serial receiver
buffer to the parallel FPGA interface (
Figure 1–3
).
Figure 1–3. Stratix II GX Receiver Block Diagram
Receiver Analog Circuits
Receiver Digital Logic
De-
serializer
Clock
Recovery
Unit
Receiver
PLL
Deskew
FIFO
Word
Aligner
Rate
Match
FIFO
8B/10B
Decoder
Byte
De-
serializer
Byte
Ordering
RX Phase
Compen-
sation
FIFO
Reference
Clock