Altera Transceiver Signal Integrity - Manual (Page 26)

6–8 Chapter 6: Stratix IV GX Transceiver Signal Integrity Demonstration
Running the Demonstration Application and Test Designs
Transceiver Signal Integrity Development Kit, December 2011 Altera Corporation
Stratix IV GX Edition User Guide
Reverse serial (Pre CDR) — Configures the transceiver channel in reverse serial (Pre
CDR) mode. The received serial data input is looped to the transmit buffer before it
passes through the RX CDR. Data checkers are not available for this option.
EyeQ Tab
This tab is only available when signal_integrity_demo3.sof is loaded. The options set
the phase step to move the sampling point of the recovered data. For more
information about this feature, refer to “EyeQ” in the
Stratix IV Dynamic
Reconfiguration chapter in volume 2 of the Stratix IV Device Handbook.
The following EyeQ features can be used in channels configured up to 6 Gbps:
Manual — Sets the phase step from 0 to 31. Once the GUI and the hardware computes
3*10E12 bits, the GUI displays the bit error rate (BER) for the phase step, plots the
value, and records the BER information for each phase step in a .csv format. The
block
stats.csv file is saved in the same folder from which the
application is launched.
Automatic — Automatically sequences through the phase steps 0-31, plots the value,
and records the BER information for each phase step in a .csv format.
1
For proper GUI operation, close all the .csv files previously created by the GUI before
launching the GUI.
To estimate the eye opening, use the following equation:
Eye opening (as a % of unit interval) = N * 1/32 * 100 +/- 3%,
where N is the number of phase steps with no errors.