1.1.3 Transmitter

The transceiver output includes features such as output swing, termination, and de-emphasis. When PCIESS is used within a device, the Libero SoC software configures the transmitter with all the necessary output features. For more information, see PolarFire Family Transceiver User Guide.

Important: In PCIe subsystem, the receiver detection circuitry within the transmitter is bypassed and the link training and status state machine (LTSSM) state moves to “polling.compliance” state (when 50 Ω is terminated to the Transmitter) when REFCLK is available and TX PLL is locked. The link training remains unaffected when an active receiver is connected. This causes the optional key-sight protocol test card (PTC) test (LOOPBACK_THROUGH_CONFIG) to fail. To pass the test, set the PMA_RXPLL_FLOCK_SEL bit to 0 when LTSSM is in “polling.compliance” state and set to 1 in other states.