Xilinx Virtex UltraScale+ FPGAs

The following table denes the RX buer aributes.
Table 65: RX Buffer Attributes
Attribute Type Description
CH[0/1]_RX_PCS_CFG0 16-bit Binary Reserved. Use the recommended value from the
Wizard.
CH[0/1]_RXFIFO_UNDERFLOW 1-bit Binary A value of 1 indicates FIFO underflow.
For channel 0, bit[8] of DRP Address 0x48B.
For channel 1, bit[8] of DRP Address 0x68B.
Note: This is a read-only aribute.
CH[0/1]_RXFIFO_OVERFLOW
1-bit Binary A value of 1 indicates FIFO overflow.
For channel 0, bit[9] of DRP Address 0x48B.
For channel 1, bit[9] of DRP Address 0x68B.
Note: This is a read-only aribute.
RX FEC
The Integrated KP4 Reed-Solomon Forward Error Correcon (RS-FEC) provides a robust mul-bit
error detecon/correcon algorithm that protects up to 2 x 58 Gb/s or 1x116 Gb/s electrical and
opcal links. This secon describes the operaon of the Integrated KP4 RS-FEC within the
UltraScale+™ device GTM transceivers.
KP4 FEC is based on the RS(544,514) code, which encodes message blocks of 5140 bits to
produce codewords of 5440 bits. For a detailed descripon of the RS-FEC sublayer in Ethernet,
including the denion of the KP4 FEC code, refer to clause 91 of the IEEE Standard for Ethernet
(IEEE Std 802.3-2015). The same FEC code is used in other standards such as OTN FlexO and
Interlaken.
The Integrated KP4 RS-FEC for each GTM dual is composed of two logical slices for each
channel. These can operate as two independent RS-FEC processing units at up to 58 Gb/s each,
or as one unied unit at up to 116 Gb/s. When operang at up to 116 Gb/s, data is transmied
and received over four virtual FEC lanes as described in IEEE 802.3-2015 clause 91. When
operang as 2 x 58 Gb/s, data can be transmied and received over two virtual FEC lanes per
58 Gb/s channel, or as a raw data stream (one virtual lane) with oponal PN scrambling for
backplane operaons. The general principle of operaon of the FEC is the same whichever mode
is chosen.
Chapter 4: Receiver
UG581 (v1.0) January 4, 2019 www.xilinx.com
Virtex UltraScale+ GTM Transceivers 106
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