Once links are created, they are added to the Links view (see the following figure) which is the primary and best way to change link settings and view status.
Each row in the Links window represents a link. Common and useful status and controls are enabled by default, so the health of the links can be quickly seen. The various settings that can be viewed in the Links window's table columns are shown in the following table.
| Link View Column Name | Description |
|---|---|
| Name | The name of the link |
| TX | The GT location of the transmitter |
| RX | The GT location of the receiver |
| Status | If linked (meaning the incoming RX data as expected). Status displays the measured line rate. Otherwise, it displays "No Link". |
| Bits | The measured number of bits received. |
| Errors | The measured number of bit errors by the receiver. |
| BER | Bit Error Ratio = (1 + Errors) / (Bits). |
| BERT Reset | Resets the received bits and error counters. |
| RX Pattern | Selects which pattern the receiver is expecting. |
| TX Pattern | Selects which pattern the transmitter is sending. |
| TX Pre-Cursor | Selects the pre-cursor emphasis on the transmitter. |
| TX Post-Cursor | Selects the post-cursor emphasis on the transmitter. |
| TX Diff Swing | Selects the differential swing values for the transmitter. |
| DFE Enabled | Selects whether the Decision Feedback Equalizer is enabled on the receiver (not available for all architectures). |
| Inject Error | Injects a single bit error into the transmit path. |
| TX Reset | Resets the transmitter. |
| RX Reset | Resets the receiver and BERT counters (see BERT Reset). |
| Loopback Mode |
Selects the loopback mode on the receiver GT. Warning: Changing this value might effect the link status depending on the system topology. |
| Termination Voltage | Selects the termination voltage of the receiver. |
| RX Common Mode | Selects the RX Common Mode setting of the receiver. |
| TXUSERCLK Freq | Shows the measured TXUSERCLK frequency in MHz. |
| TXUSERCLK2 Freq | Shows the measured TXUSERCLK2 frequency in MHz. |
| RXUSERCLK Freq | Shows the measured RXUSERCLK frequency in MHz. |
| RXUSERCLK2 Freq | Shows the measured RXUSERCLK2 frequency in MHz. |
| TX Polarity Invert | Inverts the polarity of the transmitted data. |
| RX Polarity Invert | Inverts the polarity of the received data. |
It is possible to change the values of a given property for all links in a link group by changing the setting in the link group row. For instance, changing the TX Pattern to "PRBS 7-bit" in the "Link Group 0" row changes the TX Pattern of all the links to "PRBS 7-bit". If not all the links in the group have the same setting, "Multiple" appears for that column in the link group row.
When the In System IBERT IP is used in your design, only a subset of the link settings apply. The table below lists the applicable link settings.
| Link view column name | Description |
|---|---|
| TX | The GT location of the transmitter |
| RX | The GT location of the receiver |
| TX Pre-Curser | Selects the pre-curser emphasis on the transmitter. |
| TX Post-Cursor | Selects the post-cursor emphasis on the transmitter. |
| TX Diff Swing | Selects the differential swing values for the transmitter. |
| DFE Enabled | Selects whether the Decision Feedback Equalizer is enabled on the receiver (not available for all architectures). |