Xilinx’s IBERT tool was used to create a measurement of each GTP channel’s eye diagram when using a loopback mode. Eye diagrams for each of the BRK7360 peripherals were captured using this tool with a simple loopback cable attached to each peripheral. While results may vary, these are typical captures and actually represent the worst case capture over all channels for each peripheral. Decreasing the serial transfer rate can improve the performance of each channel. Please see the Gigabit Transceivers page for IBERT diagrams of more direct loopback performance without these connectors. The IBERT settings used for these tests are the same as those used for the loopback tests on the Gigabit Transceivers page.
The following parts were used as loopback cables, etc.
|COMPONENT||MANUFACTURER / PN||DIGI-KEY||MOUSER|
|U.FL Cable (200mm)||Hirose Electric|
SFP – 3.3Gbps
A Finisar SFP module was inserted into each SFP port with a short length of fiber connecting the TX port of the Finisar module to the RX port in a loopback configuration. Due to the performance of the selected module only 3.3Gbps was used. The image below represents the worst of the scans from each SFP cage/connector. This worst case was captured with GTX 115 Ch 2.
U.FL – 8Gbps
200mm U.FL to U.FL cables were used to loop each GTX TX back to their respective RX connections. The image below represents the worst of the scans from each set of U.FL connectors. This worst case was captured with GTX115 Ch 1.
SMA – 8Gbps
6 inch SMA to SMA cables were used to connect the GTX 116 Ch 0 TXp/n and RXp/n together in a loopback configuration.
SATA – 8Gbps
Due to the configuration of the SATA ports on the BRK7360 a crossover SATA cable must be used to loop back the connection properly. In these tests an 8 inch crossover SATA cable was connected between the SATA ports in all three combinations (1<->2, 2<->3, and 1<->3). The scan below represents the worst result from each of these combinations. This worst case was captured between GTX116 Ch 2 TX and Ch 1 Rx.