Ethernet Subsystem Intel® FPGA IP User Guide: Early Access Customer Release

ID 773413
Date 4/14/2023

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4.1.10. enable_loopback for E-Tile (0x7)

Issuing the enable_loopback SAL command enables internal serial loopback mode on PMA. Below are the steps carried out by NIOS Firmware to enable serial loopback for E-tile transceiver PMA.
  1. Write the PMA attribute code (0x0008) and data (0x0101) to the PMA Avalon® Mapped-memory reconfiguration interface registers 0x84 to 0x87.
  2. Issue a PMA attribute code request by setting 0x90[0] to 1.
  3. Verify that the PMA attribute code is sent to the PMA by verifying that 0x8A[7] is asserted.
  4. Verify that 0x8B[0] de-asserts to indicate that the PMA attribute code transaction is completed.
  5. Read 0x89 to 0x88 to determine PMA attribute code is returning 0x0008.
  6. Write 0x8A[7] to 1 to clear the 0x8A[7] value.