DP83822IF: PHY Auto negotiation failes + Link not established

Hello,

Allow me to look at this and please expect response by my EoD.

Sincerely,

Gerome

Hello,

How are you reset PHY? Via which registers?

What is link partner, cable type and length used?

Is there anything triggering this linkdown, or is it link down at powerup?

Can you please go through this document and try out the steps listed here to establish baseline debugging status and understanding of the system?

Sincerely,

Gerome

Hello Gerome, thanks for your reply, i will go through this document and let you know. 

i am resetting the PHY using register 0  - first i am setting bit 11 to '1' and then bits 9 and 15.

the device can be connected using two types of cables  (both length of 1m)

1, one is M8 to M8 - so Phy to Phy (OUT from one drive and IN to another) 

2, also can be connected via M8 to RJ45 -  (usually will be connected to a motion controller / Master) 

when link down its 99% of the times at powerup, however we also noticed that while motor running that the phy losses its link and is not communicative while motor is running - this is a safety issue as well - big concern but harder to reproduce

Hello,

For now, I would like to focus on the controllable issue; link down at powerup.

You are stating that PHY is unable to linkup at startup, but issuing a register/software reset would fix the issue. So PHY is able to linkup in the first place, but there a timing aspect that is going on. 

Some questions:

- If no reset is given, will PHY forever not link up?

- Can you please confirm power-on requirements have been met per datasheet?

- What is the link partner for both PHYs? Could you try if the in and out ports are connected to each other as spotcheck if issue does not lie on DUT but on link partner?

Sincerely,

Gerome

Hi Gerome, 

unfortunately I was sick with Covid the last few days and did not have a change to work on a solution -

* i will test today and see if the PHY will resume connection on its own - without reset command.

* i will ask my HW guy about the Power-up requirements - But i believe it was met

 the phys are connected to each other i have two drive (each has two phys which we set as Phy0(IN) and Phy1(OUT) in our setup the link partner are one drive's Phy0 and one drive's Phy1 

We have noticed that in register 0x04D1 Energy Efficient Ethernet Configuration Register #2  bit0 is strap register but in our schematic it is set to 0 but we read 1, therefor i would like to send you our HW design schematics - do you have a private email i can sent it over to you?

Thanks

Hello,

Please reach out to your field representative for further email communication.
Sincerely,

Gerome

PHy will not resume connection on its own - once link was not established at startup - waited 5 minutes ( i believe its enough) and not link up (just for the test after the waited time, i reset via command and link was established)

our Reset signal time is 1ms, according to the data sheet we need at least 10us - so i believe we are ok

Hello,

What about the other PHY specs? Is the ramp time good? What about clock stabilization?

Without link partner, if you scope the MDI using a diff probe with 100 Ohm termination differentially, do you see the FLP?

Can you also look to compare the power sequence against our EVM?

Sincerely,

Gerome