User guide

Parameter Value Description
RX rate match insert/delete –ve
pattern (hex)
20 bits of data
specified as a hexadec‐
imal string
The first 10 bits correspond to the skip pattern
and the last 10 bits correspond to the control
pattern. The skip pattern must have neutral
disparity.
ve (volt encodes) are NRZ_L conditions where +ve encodes 0 and –ve encodes 1. ve is a running
disparity (+/–RD) specifically used with the rate matcher. Depending on the ppm difference (which is
defined by protocol) between the recovered clock and the local clock, the rate matcher adds or deletes a
maximum of four skip patterns (neutral disparity). The net neutrality is conserved even after the skip
word insertion or deletion because the control words alternate between positive and negative disparity.
In the following figure, the first skip cluster has a /K28.5/ control pattern followed by two /K28.0/ skip
patterns. The second skip cluster has a /K28.5/ control pattern followed by four /K28.0/ skip patterns.
The rate match FIFO deletes only one /K28.0/ skip pattern from the first skip cluster to maintain at
least one skip pattern in the cluster after deletion. Two /K28.0/ skip patterns are deleted from the
second cluster for a total of three skip patterns deletion requirement.
The rate match FIFO can insert a maximum of four skip patterns in a cluster, if there are no more than
five skip patterns in the cluster after insertion.
Figure 2-122: Rate Match FIFO Deletion with Three Skip Patterns Required for Deletion
tx_parallel_data
rx_parallel_data
First Skip Cluster
Second Skip Cluster
Three Skip Patterns Deleted
K28.5 K28.0 K28.0 K28.5 K28.0 K28.0 K28.0 K28.0
K28.5 K28.0 K28.5 K28.0 K28.0 K28.0
Note: /K28.5/ is the control pattern and /K28.0/ is the skip pattern
In the following figure, /K28.5/ is the control pattern and neutral disparity /K28.0/ is the skip pattern.
The first skip cluster has a /K28.5/ control pattern followed by three /K28.0/ skip patterns. The second
skip cluster has a /K28.5/ control pattern followed by two /K28.0/ skip patterns. The rate match FIFO
inserts only two /K28.0/ skip patterns into the first skip cluster to maintain a maximum of five skip
patterns in the cluster after insertion. One /K28.0/ skip pattern is inserted into the second cluster for a
total of three skip patterns to meet the insertion requirement.
UG-01143
2015.05.11
Rate Match FIFO in Basic (Single Width) Mode
2-299
Implementing Protocols in Arria 10 Transceivers
Altera Corporation
Send Feedback