DP83867CR: Unable to auto-negotiate

Danilo A.

Part Number: DP83867CR

Hi Team,

We would like to ask your help regarding the customer's concern below.

We are developing an ethernet product and have found that we are unable to get our DP83867CR PHY to auto-negotiate, and we have found that the PHY has reported that channel C has reverse polarity. After much review, we are unable to determine why this is. Is there any errata associated with this problem?

I have attached a PDF of the ethernet page if you would like to confirm we have correctly connected the PHY to the RJ45 magnetics. It should be noted that we have installed the bootstrap resistors for Auto-Negotiation (R81 and R92) so that it is in mode 3.

We also have found some additional problems when looking at the PHY registers. Many of the registers do not have the default values stated in the Datasheet. This includes the PHY ID registers (PHYIDR1, PHYIDR2). They are both reading 0x0000.

OMB Ethernet.pdf

Thank you for your support!

Regards,

Danilo

over 4 years ago

0 Vikram Sharma over 4 years ago

TI__Genius 16030 points

Hello Danilo,

I suspect that there is some power sequence/external oscillator stablization issue and because of which you are not able to read the registers properly. Can you try applying the pin reset (on resetn pin) when this issue occurs and see if it recovers the registers to correct default state?

Regards,

Viram

0 Thomas Livick over 4 years ago in reply to Vikram Sharma

Prodigy 70 points

I have asserted and de-asserted the reset line (resetn) of the PHY by hand through a wire to gnd and our firmware engineer reported that we have the same results.

0 Thomas Livick over 4 years ago in reply to Vikram Sharma

Prodigy 70 points

Our firmware engineer has also informed me that when he initializes the PHY, he sets bit 15 of the CTRL register. From the datasheet, it looks as though this register bit accomplishes the same thing as the resetn pin.

0 Vikram Sharma over 4 years ago in reply to Thomas Livick

TI__Genius 16030 points

Hello Thomas,

Can customer please share the following :

1. Snapshot of scope capturing :

a. Rise time of each supply of PHY.

b. 25MHz_PHY with respect to the supply ramping up.

2. Is it only on one board or the same has been tested on another samples/boards (to rule out issues like soldering etc).

You may share it with me over TI email ID also.

Regards,

Vikram

0 Thomas Livick over 4 years ago in reply to Vikram Sharma

Prodigy 70 points

Hello Vikram,

Could you provide your TI email, I cannot seem to locate it.

Thanks,

Tom

0 Vikram Sharma over 4 years ago in reply to Thomas Livick

TI__Genius 16030 points

I saw an email regarding this today and I approved the data sharing on email.

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DP83867CR: Unable to auto-negotiate