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Transmitter PCS Datapath
Table 1-11: Blocks in the Transmitter PCS Datapath
Functionality
Block
• Compensates for the phase difference between the low-speed parallel
clock and the FPGA fabric interface clock, when interfacing the
transmitter PCS with the FPGA fabric directly or with the PCIe hard
IP block
• Supports operation in phase compensation and registered modes
Transmitter Phase Compensation
FIFO
• Halves the FPGA fabric–transceiver interface frequency at the
transmitter channel by doubling the transmitter input datapath
width
• Allows the transmitter channel to operate at higher data rates with
the FPGA fabric–transceiver interface frequency that is within the
maximum limit
• Supports operation in single- and double-width modes
Byte Serializer
• Generates 10-bit code groups from 8-bit data and the 1-bit control
identifier in compliance with Clause 36 of the IEEE 802.3 specifica-
tion
• Supports operation in single- and double-width modes and running
disparity control
8B/10B Encoder
• Enables user-controlled, bit-level delay in the data prior to
serialization for serial transmission
• Supports operation in single- and double-width modes
Transmitter Bit-Slip
Transmitter Phase Compensation FIFO
The transmitter phase compensation FIFO is four words deep and interfaces with the transmitter channel
PCS and the FPGA fabric or PCIe hard IP block. The transmitter phase compensation FIFO compensates
for the phase difference between the low-speed parallel clock and the FPGA fabric interface clock.
Figure 1-22: Transmitter Phase Compensation FIFO
TX
Phase
Compensation
FIFO
Datapath from the FPGA
Fabric or PIPE Interface
tx_coreclk
tx_clkout
coreclkout
Datapath to the Byte Serializer
or the 8B/10B Encoder or Serializer
wr_clk
rd_clk
The transmitter phase compensation FIFO supports two operations:
• Phase compensation mode with various clocking modes on the read clock and write clock
• Registered mode with only one clock cycle of datapath latency
Transceiver Architecture in Cyclone V Devices
Altera Corporation
CV-53001
Transmitter PCS Datapath
1-28
2013.05.06