Figure 5-6: Configuration Options for Custom Double-Width Mode (20-bit PMA–PCS Interface Width)
Word Aligner (Pattern Length)
8B/10B Encoder/Decoder
Rate Match FIFO
Byte SERDES
Manual Alignment
or Bit-Slip
Disabled
Disabled
Enabled
Enabled
Disabled
Disabled
Enabled
Disabled
Data Rate (Gbps)
GX/SX= 3.125
GT/ST= 3.2768
GX/SX= 3.125
GT/ST= 5
GX/SX= 3.125
GT/ST= 3.2768
GX/SX= 3.125
GT/ST= 5
FPGA Fabric–Transceiver
Interface Width
20-Bit
40-Bit
16-Bit
32-Bit
Rate Match FIFO in Custom Configuration
In a custom configuration, the 20-bit pattern for the rate match FIFO is user-defined. The FIFO operates
by looking for the 10-bit control pattern followed by the 10-bit skip pattern in the data, after the word aligner
restores the word boundary. After finding the pattern, the FIFO performs a skip pattern insertion or deletion
to ensure that the FIFO does not underflow or overflow a given parts per million (ppm) difference between
the clocks.
The rate match FIFO operation requires 8B/10B-coded data.
Rate Match FIFO Behaviors in Custom Single-Width Mode
The different operations available in custom single-width mode for the rate match FIFO are symbol insertion,
symbol deletion, full condition, and empty condition.
Table 5-2: Rate Match FIFO Behaviors in Custom Single-Width Mode (10-bit PMA–PCS Interface Width)
Behavior
Operation
Inserts a maximum of four skip patterns in a cluster,
only if there are no more than five skip patterns in the
cluster after the symbol insertion.
Symbol Insertion
Deletes a maximum of four skip patterns in a cluster,
only if there is one skip pattern left in the cluster after
the symbol deletion.
Symbol Deletion
Deletes the data byte that causes the FIFO to go full.
Full Condition
Inserts a /K30.7/ (9'h1FE) after the data byte that
caused the FIFO to go empty.
Empty Condition
Altera Corporation
Transceiver Custom Configurations in Cyclone V Devices
5-5
Rate Match FIFO in Custom Configuration
CV-53005
2013.05.06