DP83867E: DP83867 SGMII NO LINK

Hello,

Can you provide more information about the test that you are running? What strap configuration are you using, you can use registers 0x006e and 0x006f to confirm your desired strap configuration is being latched during start-up or reset. 

Register 0x0001 can be used to determine the status of the Link and Auto-Negotiation as well. 

Regards,

Justin 

Hi Justin,

Thank you for your reply quickly! I have dumped all the PHY registers -including the ones you asked me.

Hi Peng,

I will take time to review your register data and aim to provide a response by 5/19. Thank you for you help in resolving this.

Regards,
Justin 

Hi Peng,

It appears that the straps circuitry you are using is not strapping the desired values into the PHY. For example:

Register 0x006E bit 15 = 0 meaning Mirror Mode is strapped to Disable. LED_0 Mode 4 is not a valid strap setting, please use Mode 3 to enable Mirror Mode.

Register 0x006E bit 7 = 0 meaning Auto-Negotiation is strapped to Enable. RX_CRTL Mode 4 strap is not disabling Auto-Neg.

Try fixing these settings and observing whether that allows you to get link.

Regards,
Justin 

Hi Justin,

Thanks again for your reply. As you said, I have changed the mode of RX_CRTL to 3 to enable auto-negotiation. And register 0x0000(BMCR) is 0x1140, auto-negotiation is enabled. 

The MAC connected to 83867 is switch89551. I want to do a digital loopback from MAC 89551-> PHY-> MAC 89551. So I set port 6 of 89551 to SGMII, auto-negotiation mode, 100M, full duplex. But this digital loopback has never worked. Rgister 0x0011(PHYSTS) is 0x0002,bit 15:14 =0 meaning speed is 10M,bit 13=0 meaning half duplex. Digital Loopback is no success.

If i closed Auto-negotiation, force speed 100M, mode is full duplex. MAC 89551->83867->MAC 89551 Digital Loopback is success.

Register 0x0031(CFG4) is 0x1002. And I cannot modify  this register?

Register 0x0037(SGMII_ANEG_STS) is 0x0040. Bit 0 = 0 meaning SGMII Auto-Negotiation process not complete.Bit 1 = 0 meaning SGMII page has not been received. How should i do ?

This is my hardware schematic.

Thank you very much for taking the time to help solve this problem.

Best Regards,

Peng

Hi Justin,

Awaiting for your reply.

As this issue is very critical to us,I request you to reply at your earliest convenience.

Thanks and Regards,

Peng

Hi Peng,

There is a note in the datasheet in section 8.4.4.1 stating that Auto-Negotiation must be disabled for Near-End loopbacks, that includes digital loopback mode. If you want to continue using loopback modes with Auto-Negotiation enabled, please use an external loopback.

Regards,
Justin 

 Hi Justin,

Thank you for your support.

I have considered using external loopback before, but SGMII does not support external loopback.

The purpose of doing loopback is also to verify MAC-> PHY-> RJ45-> PC step by step. Now i close AUTO-NEGOTIATION,  the digital loopback is success, which means that MAC-> PHY is no problem.

When i close digital loopback,MAC->PHY->RJ45->PC is not link up.

Register 0x0001(BMSR) is 0x7949, bit 2 (0) meaning link not established.

Can you please let us know,what other things can be checked.

Thanks and Regards

Peng

Hi Peng, 

I want to confirm that you have updated the RX_CRTL strap from the schematic above and register 0x0000=1140?

What is driving your need for Mirror Mode? I may have been mistaken above, in SGMII mode Mirror Mode is enabled in mode 3 & 4; your schematic shows Mirror Mode enabled. If you disable mirror mode through registers or strap, are you able to get link? This can be changed in register 0x0031[0]

Regards,
Justin 

Hi Justin,

I have updated the RX_CRTL from mode 4 to mode 3, read register 0x0000 = 0x1140.

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If you disable mirror mode through registers or strap, are you able to get link?

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Now my LED_0 use mode 4, Mirror Mode is enable, but read register 0x0031(CFG4) is 0x6B02, bit 0 is 0. And 0x006E is 0x0000, bit 15 meaning port mirroring strapped to disable.Do you have any advices?

Considering that it may be the cause of RJ45, remove RJ45 from the hardware and connect directly with network cable,but still no link.

Thanks and Regards,

Peng

Hi Justin,

Thanks for your lots of suggestions.This problem is indeed caused by the mirror enable. After we disable the Mirror Mode, the link succeeds.

Thanks and Regards,

Peng