Cyclone® V GT FPGA Development Kit User Guide

ID 792833
Date 2/21/2024
Public
Document Table of Contents

6.3.7.2. XCRV and CMOS

The XCRV and CMOS groups display the following status information during the loopback test:

Data rate—Displays the current data rate in megabytes per second (Mbps).

Freq—Displays the data rate frequency in MHz which is equivalent to Mbps.

Bits—Displays the number of bits transmitted since clicking Start.

Inserted errors—Displays the number of errors inserted by clicking Insert Error button.

Detected errors—Displays the number of bit errors detected by the error checking circuitry.

BER—Displays the bit error rate of the interface.

Status
  • PLL lock—Displays Yes if the PLL is locked.
  • Pattern Sync—Displays Yes if the receiver has detected the input data pattern.

Start—Starts the PRBS data test and begins to monitor and update screen with live test results.

Stop—Stops the PRBS data test.

Insert Error—Inserts an error into a data stream that is detected by the receiver when in loopback mode. With the Insert Error, there are differences among the three ports:
  • XCVR—Inserts 4 errors at 1 click.
  • CMOS—Inserts 1 error at 1 click.

Clear—Clears the Detected errors counter.

PMA Setting—Only available for the XCVR test. This control allows you to make changes to the PMA parameters that affect the active transceiver interface. The following settings are available for analysis:
  • Serial Loopback—Routes the selected TX output signal back to the RX input signal on-chip to verify operation without using an external loopback board.
  • VOD—Specifies the voltage output differential of the transmitter buffer.
  • Pre-emphasis tap
  • Pre—Not available.
    • First post—Specifies the amount of pre-emphasis on the first post tap of the transmitter buffer.

      Second post—Not available.

  • Equalizer—Specifies the setting for the receiver equalizer.
  • DC gain—Specifies the DC portion of the receiver equalizer.
Data Type—Specifies the type of data contained in the transactions. The following data types are available for analysis:
  • PRBS7—Pseudo-random 7-bit sequences
  • PRBS15—Pseudo-random 15-bit sequences
  • PRBS23—Pseudo-random 23-bit sequences
  • PRBS31—Pseudo-random 31-bit sequences
  • HF—Highest frequency divide-by-4 data pattern 10101010
  • LF—Lowest frequency divide-by-4 data pattern 11110000