6
Transceiver Loopback Support
2013.05.06
CV-53006
Send Feedback
The Cyclone V loopback options allow you to verify how different functional blocks work in the transceiver.
Related Information
Cyclone V Device Handbook: Known Issues
Lists the planned updates to the Cyclone V Device Handbook chapters.
Serial Loopback
This section describes the use of serial loopback as a debugging aid to ensure the enabled PCS and PMA
blocks in the transmitter and receiver channels function correctly.
Serial loopback is available for all transceiver configurations except the PIPE mode. You can use serial
loopback as a debugging aid to ensure that the enabled physical coding sublayer (PCS) and physical media
attachment (PMA) blocks in the transmitter and receiver channels are functioning correctly. Furthermore,
you can dynamically enable serial loopback on a channel-by-channel basis.
The data from the FPGA fabric passes through the transmitter channel and is looped back to the receiver
channel, bypassing the receiver buffer. The received data is available to the FPGA logic for verification.
Figure 6-1: Serial Loopback Datapath
Transmitter PCS
Transmitter PMA
Receiver PMA
Receiver PCS
FPGA
Fabric
Serial
Loopback
can be
Dynamically
Enabled
Byte
Ordering
RX
Phase
Compensation
FIFO
Byte
Deserializer
8B/10B
Decoder
Rate
Match
FIFO
Word
Aligner
Deserializer
CDR
TX
Phase
Compensation
FIFO
Byte
Serializer
8B/10B
Encoder
TX
Bit
Slip
Serializer
rx_serial_data
tx_serial_data
When you enable serial loopback, the transmitter channel sends data to both the
tx_serial_data
output
port and to the receiver channel. The differential output voltage on the
tx_serial_data
port is based
on the selected differential output voltage (V
OD
) settings.
©
2013 Altera Corporation. All rights reserved. ALTERA, ARRIA, CYCLONE, HARDCOPY, MAX, MEGACORE, NIOS, QUARTUS and STRATIX words
and logos are trademarks of Altera Corporation and registered in the U.S. Patent and Trademark Office and in other countries. All other
words and logos identified as trademarks or service marks are the property of their respective holders as described at
www.altera.com/common/legal.html
. Altera warrants performance of its semiconductor products to current specifications in accordance with
Altera's standard warranty, but reserves the right to make changes to any products and services at any time without notice. Altera assumes
no responsibility or liability arising out of the application or use of any information, product, or service described herein except as expressly
agreed to in writing by Altera. Altera customers are advised to obtain the latest version of device specifications before relying on any published
information and before placing orders for products or services.
www.altera.com
101 Innovation Drive, San Jose, CA 95134