GTS Transceiver PHY User Guide: Agilex™ 3 FPGAs and SoCs

ID 848344
Date 8/04/2025
Public
Document Table of Contents

3.14.2.3. GTS Attribute Access Method Example 3: Enable or Disable Polarity Inversion of the PMA

The following examples demonstrate the steps to perform polarity inversion for the GTS PMA physical lane 0.

To reverse the polarity of TX p and n pins:

  1. Assert TX reset.
  2. Write 0x1A065 to address 0xA403C.
  3. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1.
  4. Write 0x12065 to address 0xA403C.
  5. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0.
  6. Deassert TX reset.

To reverse the polarity of RX p and n pins:

  1. Assert RX reset.
  2. Write 0x1A066 to address 0xA403C.
  3. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1.
  4. Write 0x12066 to address 0xA403C.
  5. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0.
  6. Deassert RX reset.

To revert back the polarity of TX p and n pins:

  1. Assert TX reset.
  2. Write 0x0A065 to address 0xA403C.
  3. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1.
  4. Write 0x02065 to address 0xA403C.
  5. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0.
  6. Deassert TX reset.

To revert back the polarity of RX p and n pins:

  1. Assert RX reset.
  2. Write 0x0A066 to address 0xA403C.
  3. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 1.
  4. Write 0x02066 to address 0xA403C.
  5. Poll address 0xA4040 until bit 14 = 0 and bit 15 = 0.
  6. Deassert RX reset.