Altera Cyclone V Device Handbook page 317

1-30
Byte Serializer in Double-Width Mode
Byte Serializer in Double-Width Mode
The operation in double-width mode is similar to that of single-width mode. For example, in double-width
mode with a channel width of 32 bits, the byte serializer forwards tx_parallel_data[15:0] first,
followed by tx_parallel_data[31:16].
Table 1-13: Input and Output Data Width of the Byte Serializer in Double-Width Mode for Cyclone V Devices
Mode
Double-width
If you select the 8B/10B Encoder option, the 8B/10B encoder uses the output from the byte serializer.
Otherwise, the byte serializer output is forwarded to the serializer.
8B/10B Encoder
The 8B/10B encoder supports operation in single- and double-width modes with the running disparity
control feature.
8B/10B Encoder in Single-Width Mode
In single-width mode, the 8B/10B encoder generates 10-bit code groups from 8-bit data and 1-bit control
identifier with proper disparity according to the PCS reference diagram in the Clause 36 of the IEEE 802.3
specification. The 10-bit code groups are generated as valid data code-groups (/Dx.y/) or special control
code-groups (/Kx.y/), depending on the 1-bit control identifier.
Figure 1-23: 8B/10B Encoder in Single-Width Mode
The IEEE 802.3 specification identifies only 12 sets of 8-bit characters as /Kx.y/. If other sets of 8-bit
characters are set to encode as special control code-groups, the 8B/10B encoder may encode the output 10-
bit code as an invalid code (it does not map to a valid /Dx.y/ or /Kx.y/ code), or unintended valid /Dx.y/
code, depending on the value entered.
In single-width mode, the 8B/10B encoder translates the 8-bit data to a 10-bit code group (control word or
data word) with proper disparity. If the tx_datak input is high, the 8B/10B encoder translates the input
Altera Corporation
Input Data Width to Output Data Width from the
the Byte Serializer
32 16
40 20
datain[7:0]
control identifier
disparity controls
Byte Serializer
8B/10B Encoder
dataout[9:0]
Transceiver Architecture in Cyclone V Devices
Byte Serializer Output Ordering
Least significant 16 bits of the 32-
bit output first
Least significant 20 bits of the 40-
bit output first
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2013.05.06