User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 630
UG585 (v1.11) September 27, 2016
Chapter 21: Programmable Logic Description
Receiver
The receiver is fundamentally a serial-to-parallel converter, changing the incoming bit-serial
differential signal into a parallel stream of words, each 16, 20, 32, 40, 64, or 80 bits. This allows the
designers to trade-off internal datapath width versus logic timing margin. The receiver takes the
incoming differential data stream, feeds it through programmable linear and decision feedback
equalizers (to compensate for PC board and other interconnect characteristics), and uses the
reference clock input to initiate clock recognition. There is no need for a separate clock line. The data
pattern uses non-return-to-zero (NRZ) encoding and optionally guarantees sufficient data
transitions by using the selected encoding scheme. Parallel data is then transferred into the PL using
the RXUSRCLK clock. For short channels, the transceivers offers a special low power mode (LPM) for
additional power reduction.
Out-of-Band Signaling
The transceivers provide out-of-band (OOB) signaling, often used to send low-speed signals from
the transmitter to the receiver while high-speed serial data transmission is not active. This is typically
done when the link is in a powered-down state or has not yet been initialized. This benefits PCI
Express and SATA/SAS applications.
For more details on GTX Transceivers, see UG476
, 7 Series FPGAs GTX Transceiver User Guide.