DP83867IR: HW/SW setting for Auto negotiation

Hi Ohashi,

• Are you able to read BMCR multiple times to see any update on the 0x0000 register?
• What mode are you operate in your scenario: Auto-negotiation or Force mode?
• Are able to power cycle it and see rather that change the result?
• Did you write any register or run any driver before you read 0x0000 register value?
• Could you let me know what strap resistor or pin did you use to disable the auto negotiation during strapping?

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Thank you,

Hillman Lin

Hi Lin,

Thanks for your reply. i have checked with the customer

• Are you able to read BMCR multiple times to see any update on the 0x0000 register?
  • No update when reading multiple times.
• What mode are you operate in your scenario: Auto-negotiation or Force mode?
  • Forced mode
• Are able to power cycle it and see rather that change the result?
  • No change
• Did you write any register or run any driver before you read 0x0000 register value?
  • Didn't do any write/run before reading BMCR.
• Could you let me know what strap resistor or pin did you use to disable the auto negotiation during strapping?
  • Used RX_CTRL pin to disable the Auto-neg

If they set the HW setting to Auto-neg disable, it should be reflected to BMCR register, right?

Regards,

Ohashi

Hi Ryoma,

Yes, you are correct, If they set the HW setting to Auto-neg disable, it should be reflected to BMCR register. It seems like the strapping works but just register 0x0000 is not updated. I will double check on our side as well. Thank you for pointing it out.

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Thank you,

Hillman Lin

Hi Ryoma,

We test it in the lab using our own EVM, we are able to see auto negotiation disable after the 867EVM  RX_CTRL pull high. May I ask what is the resistor value you pull up to strap the RX_CTRL pin

• What is your current concern on this issue? Are you trying to use force mode or auto negotiation mode?
• We usually don't recommend using force mode. If you want to run everything into 100mpbs do recommend using disable advertisement feature.

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Regards,

Hillman Lin

Hi Lin,

Thanks for your quick support! Got it that BMCR has changed in your EVM. 

Hillman Lin said:

May I ask what is the resistor value you pull up to strap the RX_CTRL pin

Set to Mode4 by Rhi=2.49kΩ　Rlo=open, as written in the datasheet.

What do you think is the root cause of this problem?

Hillman Lin said:

We usually don't recommend using force mode. If you want to run everything into 100mpbs do recommend using disable advertisement feature.

Could you kindly show the instruction for this way of forcing to 100M?

Regards,

Ohashi

Hi Ryoma,

• If you are trying to do only 100mbps communication. we recommend disable advertisement by writing 0x0009 bit[8] and bit[9] = 0. And writing 0x0004 bit[6] and bit[5] = 0.

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Regards,

Hillman Lin

Hi Lin,

Thanks for your reply. Got it about how to force on 100Mbps.

What do you think about the issue of BMCR not changed to Auto-neg disable?

Should I ask them to provide us the full register dump?

Regards,

Ohashi

Hi Ryoma,

Could you ask customer to probe RX_DV pin in strap during hard reset or power cycle. May I ask why do customer concern about this issue? Is the problem with the PHY not linking up?

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Regards,

Hillman Lin