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ChipScope Pro Software and Cores User Guide
UG029 (v14.3) October 16, 2012
Chapter 4:
Using the ChipScope Pro Analyzer
(green), the measured line rate is displayed. If the channel is not linked, it displays NO
Link (red).
The CPLL/QPLL Status indicator shows the lock status of the CPLL/QPLL that is
connected to the GTX transceiver. The valid states of this status indicator are CPLL/QPLL
LOCKED (green) or CPLL/QPLL NOT LOCKED (red).
The Loopback Mode setting controls the loopback mode of a particular GTX transceiver
channel. The valid choices for loopback mode are:
•
None: no feedback path is used.
•
Near-End PCS: the circuit is wholly contained within the near-end GTX transceiver
channel. It starts at the TX fabric interface, passes through the PCS, and returns
immediately to the RX fabric interface without ever passing through the PMA side of
the GTX channel.
•
Near-End PMA: the circuit is wholly contained within the near-end GTX transceiver
channel. It starts at the TX fabric interface, passes through the PCS, through the PMA,
back through the PCS, and returns to the RX fabric interface.
•
Far-End PMA: the circuit originates and ends at some external channel endpoint (for
example, external test equipment or another device) but passes through the part of the
GTX transceiver channel. For this GTX transceiver loopback mode, the signal comes
into the RX pins, passes through the PMA circuitry, and returns immediately to the TX
pins.
•
Far-End PCS: the circuit originates and ends at some external channel endpoint (for
example, external test equipment or another device) but passes through part of the
GTX transceiver channel. For this GTX loopback mode, the signal comes into the RX
pins, passes through the PMA, through the PCS, back through the PMA, and returns
to the TX pins.
•
Far-End Fabric: the circuit originates and ends at some external channel endpoint (for
example, external test equipment or another device) but passes through the entire
GTX transceiver channel and related fabric logic. For this GTX transceiver loopback
mode, the signal comes into the RX pins, passes through the PMA and PCS, through a
shallow fabric-based FIFO, back through the PCS and PMA, and finally returns to the
TX pins.
The Channel Reset button resets the GTX transceiver channel by clearing and resetting all
internal PMA and PCS circuitry as well as the related fabric interfaces.
The TX Polarity Invert setting controls the polarity of the data sent out of the TX pins of the
GTX transceiver channel. To change the polarity of the TX side of the GTX transceiver,
check the TX Polarity Invert box.
The TX Bit Error Inject button inverts the polarity of a single bit in a single transmitted
word. The receiver endpoint of the channel that is connected to this transmitter should
detect a single bit error.
The TX Diff Output Swing combo box controls the differential swing of the transmitter.
Change the value in the combo box to change the swing.
The TX Pre-Cursor and TX Post-Cursor combo boxes control the amount of pre-emphasis
on the transmitted signal. Change the value in the combo boxes to change the pre-
emphasis settings.
The RX Polarity Invert setting controls the polarity of the data received from the RX pins of
the GTX transceiver channel. To change the polarity of the RX side of the GTX transceiver,
check the RX Polarity Invert box.
