To clock six identical channels with a single clock, perform these steps:
• Instantiate the
rx_coreclkin
port for all the identical receiver channels (
rx_coreclkin[5:0]
).
• Connect
rx_clkout[4]
to the
rx_coreclkin[5:0]
ports.
• Connect
rx_clkout[4]
to the receiver data and control logic for all six channels.
Resetting or powering down channel 4 leads to a loss of the clock for all six channels.
Note:
The common clock must have a 0 ppm difference for the write side of the RX phase compensation FIFO of
all the identical channels. A frequency difference causes the FIFO to under run or overflow, depending on
whether the common clock is faster or slower, respectively.
You can drive the 0 ppm common clock driver from one of the following sources:
•
tx_clkout
of any channel in non-bonded receiver channel configurations with the rate matcher
•
rx_clkout
of any channel in non-bonded receiver channel configurations without the rate matcher
•
tx_clkout[0]
in bonded receiver channel configurations
• Dedicated
refclk
pins
The Quartus II software does not allow gated clocks or clocks generated in the FPGA logic to drive
the
rx_coreclkin
ports.
Note:
You must ensure a 0 ppm difference. The Quartus II software is unable to ensure a 0 ppm difference
because it allows you to use external pins, such as dedicated
refclk
pins.
Note:
Document Revision History
The table below lists the revision history for this chapter.
Table 2-10: Document Revision History
Changes
Version
Date
• Updated Content for Quartus II software version 13.0
• Updated figure "Input Reference Clock Sources for Transceiver
Channels"
• Added a section on "Dual-Purpose RX/refclk Pins".
• Added link to the known document issues in the Knowledge Base.
2013.05.06
May 2013
• Reorganized content and updated template.
• Updated for the Quartus II software version 12.1.
2012.11.19
November 2012
Minor editorial changes.
1.1
June 2012
Initial release.
1.0
October 2011
Transceiver Clocking in Cyclone V Devices
Altera Corporation
CV-53002
Document Revision History
2-28
2013.05.06