GTS Ethernet Intel® FPGA Hard IP User Guide

ID 817676
Date 8/05/2024
Public

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11.1.2. Enable MAC Loopback

The output of the TX MAC is connected to the input of the RX MAC, forming a loopback connection.
Figure 71. Enable MAC Loopback

Follow these steps to enable MAC Loopback:

  1. Write 0x1 to bit 0 of the eio_sys_rst(0x108) to reset the GTS Ethernet Intel® FPGA IP.
  2. If internal serial loopback is enabled, disable it by:
    1. Writing 0x0A340 to address 0xA403C
    2. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1
    3. Write 0x02340 to address 0xA403C
    4. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0
  3. Perform MAC loopback by writing 0x04 to 0x50028register.
  4. Write 0x1 to bit 0 of ignore_rx_lock2data (0x10018).
  5. Deassert the soft global reset by writing 0x0 to bit 0 of eio_sys_rst(0x108).
  6. Write 0x1 to bit 0 of hardware packet client control hw_pc_ctrl register at address 0x00 to instruct the packet client to transmit data and start the packet generator. Alternatively, write 0x1 to 0x100000 register.
  7. Check MAC statistics by running the command chkmac_stats.