DP83822HF: Linkup Status (Basic Mode Status Register (BMSR) bit2) changes on its own(?)

Kondo Akira

Prodigy 80 points

Part Number: DP83822HF

Hello.

In the following conditions, Linkup Status (Basic Mode Status Register (BMSR) bit2) changes on its own.

- Power on DP83822HF (removed the fiber cable).

In this time, Linkup Status = 0 (Link not established).

- Wait for several tens of minutes.

=> It may occur intermittently, Linkup Status = 1 (Valid link established).

In this case, LOS signal is not chaged.

Do yo have any idea what this means?

over 4 years ago

0 Vikram Sharma over 4 years ago

TI__Genius 16030 points

Hello,

Were you able to capture the waveform at the LOS signal too?

Regards,

Vikram

0 Kondo Akira over 4 years ago in reply to Vikram Sharma

Prodigy 80 points

Hi Vikram.

I didn't capture the waveform at the LOS signal.

DP83822HF's LOS signal is input to FPGA, and I checked olny FPGA data.

What is the purpose of capturing the waveform at the LOS singal?

Can the LOS signal fluctuate instantaneously?

0 Vikram Sharma over 4 years ago in reply to Kondo Akira

TI__Genius 16030 points

Hello,

My understanding was that LOS was the signal coming from SFP and going to PHY's SD_IN. Is'nt that so? If it is coming from SFP, I am expecting that there is some mis-behaviour or glitch or very slow transition etc from SFP side that is not matching the PHY's requirement.

0 Kondo Akira over 4 years ago in reply to Vikram Sharma

Prodigy 80 points

Hi Vikram.

Sorry, I have a mistake.

My desgin is below.

SFP:LOW => DP83822HF:SD_IN(LED_1/GPIO1) & FPGA:Input (forking)

I try to capture the waveform at the LOS signal.

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DP83822HF: Linkup Status (Basic Mode Status Register (BMSR) bit2) changes on its own(?)