Linux/DP83620: Use DP83620 as fiber mode,could not ping

edwin huang

Part Number: DP83620

Tool/software: Linux

Dear all,

I use DP83620 for a long time, but before I use it as electric 100Mbps port. In our application, EMC becomes more serious, So I use DP83620 as fiber mode but I couldn't ping by fiber.

SFP_TX_Disable is pull down to GND. FX_SD is set to high in FPGA. And use switch to decide the PHY work as electric or fiber mode.fiber_vv.pdf

over 6 years ago

0 Aniruddha Khadye over 6 years ago

TI__Mastermind 18425 points

Hello Edwin,

Ping depends on higher layer protocols which are not handled by the PHY. Can you confirm that you are establishing Link up when operating in Fiber mode?

Moving from Copper to Fiber needs some design changes on the board. Can you confirm that the changes are as per DP83620 requirements? You can use the DP83620 EVM schematics as reference: www.ti.com/.../snlr004.pdf

-Regards,
Aniruddha

0 edwin huang over 6 years ago in reply to Aniruddha Khadye

Prodigy 20 points

Khadye, Thanks for your reply.
when change to Fiber mode, I have some changes. FX_EN is pull down, and PHY_ACT is pull up to 3.3V. And FX_SD is pull to high in FPGA, we find 62.5MHz signal is transfer from another fiber to the other fiber, we guess that PHY didn't receive it, so higher layer protocal won't reply ping frames.

0 Aniruddha Khadye over 6 years ago in reply to edwin huang

TI__Mastermind 18425 points

Hi Edwin,

Can you try connecting the signal detect pin of the Fiber transceiver to the PHY?

-Regards,
Aniruddha

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Linux/DP83620: Use DP83620 as fiber mode,could not ping