GTS Ethernet Intel® FPGA Hard IP User Guide

ID 817676
Date 8/05/2024
Public

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11.1.4. Enable External Loopback

The output TX PMA data is transmitted via the transceiver's TX pin, and the RX PMA receives input data from the transceiver's RX pin.
Enable External loopback
Follow these steps to enable PMA without loopback or external loopback:
  1. Write 0x4 to the soft_rx_rst(0x108) register to assert the soft RX reset.
  2. Write 0x0A340 to address 0xA403C.
  3. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1.
  4. Write 0x02340 to address 0xA403C.
  5. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0.
  6. De-assert RX reset by writing 0x0 to 0x108 register.
    Enabling External Loopback in the Design Example

    The design example hardware TCL script supports both internal and external loopback mode. By default, the design example is configured for external loopback. To run this mode, in the system console, execute run_test_without_loopback.