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Configuring Finisar Copper SFP 8521-3

Configuring Finisar Copper SFP 8521-3

This page explains how to configure Finisar Copper SFP 8521-3 to talk to Altera Triple-Speed Ethernet IP Core. If you use other Altera 1G Ethernet PHY IP Cores, this page still help you to understand how the PCS registers have to be set.

1000BASE-X Auto-Negotiation On configuration (No register write required)

The default setting of Finisar 8521-3 Copper SFP is 1000BASE-X Auto-Negotiation. If you use 1000BASE-T as the copper link, you don't need to access SFP's registers.

Link steps

  1. The Triple-Speed Ethernet (TSE) IP Core and the SFP start talking each other, but RJ-45 cable is still disconnected and the copper (10BASE-T/100BASE-TX/1000MBASE-T)link is not established. Because of the copper link status, the Finisar SFP sends its 1000BASE-X ability 0x0000 to the TSE (TSE's rx_frame = 0xBC420000BCB50000).
  2. TSE’s link partner ability status register (0x85) is also 0x0000.
  3. A RJ-45 cable is attached and the Finisar SFP establishes the copper link at 1000M
  4. The TSE and the Finisar SFP complete 1000BASE-X Auto-Negotiation, and TSE's led_an goes 1.

Note: Because acceptable link speed is only 1000M, auto-negotiation won’t be completed if copper link speed is 10M or 100M.

SGMII Auto-Negotiation On configuration (Register write required)

Conguring the TSE to SGMII Auto-Negotiation mode

  1. TSE PHY address offset 0x12 = 0x12D0
  2. TSE PHY address offset 0x13 = 0x0003
  3. TSE PHY address offset 0x14 = 0x0003
  4. TSE PHY address offset 0x00 = 0x1140
  5. TSE PHY address offset 0x00 = 0x9140

At this point, the Finisar Coppper SFP is still in 1000BASE-X Auto-Negotiation mode. Because of the mismatch setting, the auto-negotiation won’t be completed (TSE's led_an remains at 0).

Configuring Finisar Copper SFP to SGMII Auto-Negotiation too, and advertise 10M, 100M, and 1000M for the copper link

  1. SFP address offset 0x1B = 0x9084 (Enable SGMII mode)
  2. SFP address offset 0x09 = 0x9084 (Advertise 1000BASE-T Full and Half duplex)
  3. SFP address offset 0x04 = 0x0DE1 (Advertise 10BASE-T/100BASE-TX Full and Half duplex)
  4. SFP address offset 0x00 = 0x8140
  5. SFP address offset 0x00 = 0x9140 (Software reset)

Link Steps

  1. An RJ-45 cable is connected to the Copper SFP, and copper link is established at 1000M, and the SGMII Auto-Negotiation is completed (TSE's led_an goes 1).
  2. TSE's SGMII MAC mode link partner ability status register is 0xd801 (Copper link up at 1000M)
  3. Disconnect the RJ-45 cable
  4. Copper link is down. The SGMII auto-negotiation is still established (TSE's led_an is 1), the Finisar SFP sends its ability 0x4001 (Copper link down), and TSE's partner ability register reflects it to its register address offset 0x05.
  5. Reconnect the RJ-45 cable
  6. Copper link is re-established at 100M. The Finisar SFP sends its ability 0xd401 (Copper link up at 100M), and TSE’s partner ability register reflects it to its register address offset 0x05.


Version history
Last update:
‎02-04-2021 03:21 PM
Updated by: