User guide

Figure 5-38: Byte Serializer Block Diagram
Byte
Serializer
dataout
(to the 8B/10 Encoder
or the TX Bit Slip)
datain (from the TX FIFO)
/2,
/4
tx_clkout
Related Information
• Implementing Protocols in Arria 10 Transceivers on page 2-1
• Resetting Transceiver Channels on page 4-1
Bonded Byte Serializer
The bonded byte serializer is available in Arria 10 devices, and is used in applications such as PIPE, CPRI,
and custom applications where multiple channels are grouped together. The bonded byte serializer is
implemented by bonding all the control signals to prevent skew induction between channels during byte
serialization. In this configuration, one of the channels acts as master and the remaining channels act as
slaves.
Byte Serializer Disabled Mode
In disabled mode, the byte serializer is bypassed. The data from the TX FIFO is directly transmitted to the
8B/10B encoder, TX Bitslip, or Serializer, depending on whether or not the 8B/10B encoder and TX
Bitslip are enabled. Disabled mode is used in low speed applications such as GigE, where the FPGA fabric
and the TX standard PCS can operate at the same clock rate.
Byte Serializer Serialize x2 Mode
The serialize x2 mode is used in high-speed applications such as the PCIe Gen1 or Gen2 protocol
implementation, where the FPGA fabric cannot operate as fast as the TX PCS.
In serialize x2 mode, the byte serializer serializes 16-bit, 20-bit (when 8B/10B encoder is not enabled), 32-
bit, and 40-bit (when 8B/10B encoder is not enabled) input data into 8-bit, 10-bit, 16-bit, and 20-bit data,
respectively. As the parallel data width from the TX FIFO is halved, the clock rate is doubled.
After byte serialization, the byte serializer forwards the least significant word first followed by the most
significant word. For example, if the FPGA fabric-to-PCS Interface width is 32, the byte serializer
forwards tx_parallel_data[15:0] first, followed by tx_parallel_data[31:16].
Related Information
PCI Express (PIPE) on page 2-228
For more information about using the Serialize x2 mode in the PCIe protocol.
Byte Serializer Serialize x4 Mode
The serialize x4 mode is used in high-speed applications such as the PCIe Gen3 protocol mode, where the
FPGA fabric cannot operate as fast as the TX PCS.
UG-01143
2015.05.11
Bonded Byte Serializer
5-39
Arria 10 Transceiver PHY Architecture
Altera Corporation
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