• State Resolved
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 69 views
  • Users 0 members are here
Support feedback
Options
Options
Related

DP83869HM: DP83869_Strapping Clarification

Srikanth Kacchu1
Expert 1235 points
Part Number: DP83869HM
Other Parts Discussed in Thread: DP83869, TMDS64EVM

Tool/software:

Hi Team,

We are using TMDS64EVM. Notes under DP83869 (U20) in schematic mentioned as below:

PHY ADDRESS = 01111

Auto-negotiation, 10/100/1000 advertised, Auto-MDI-X
RGMII to Copper (1000BaseT/100Base-TX/10Base-Te)

But pull down 2.49K (R565) is provided. As per datasheet of DP83869 , it means that RGMII to Copper table is "NA" instead of "Auto-negotiation, 10/100/1000 advertised, Auto-MDI-X".

Pls clarify.

Regards,

Srikanth Kacchu

  • 0
    TI__Genius 11786 points

    Hi Srikanth, 

    I reviewed the schematic on TMDS64EVM for the latest revision. 
    Our old strap recommendation was to pull down for mode 0. 
    With LED0 pulled down, this means ANEG_DIS = 0. So the auto-negotiation is enabled. LED_1 and 2 are floating so they are also mode 0. So, the PHY is strapped to do "Auto-negotiation, 10/100/1000 advertised, Auto-MDI-X".

    Best,
    J

  • 0 in reply to J
    Expert 1235 points

    Hi J,

    Thanks for the response.

    To configure LED0 in Mode 0 (2 Level strap), Pull up is OPEN and pull down is 2.49K. For the same mode, why LED1 and LED2 has OPEN in both sides?

    Regards,

    Srikanth Kacchu

  • 0 in reply to Srikanth Kacchu1
    Expert 1235 points

    Hi J,

    When all three LED0, LED1 and LED2 pins are set in MODE0, then only it will be configured as "Auto-negotiation, 10/100/1000 advertised, Auto-MDI-X" as per datasheet table 7.12. For MODE0, Pull up should be OPEN and Pull down should be 2.49K. Pls let me know if my understanding is correct.

    Or should we consider LED0 (ANEG_DIS) separate and consider LED1 & LED2 as a group?

  • +1 in reply to Srikanth Kacchu1
    TI__Genius 11786 points

    Hi Srikanth,

    Please consider all LED pins as a group. For mode 0, we used to recommend pull up open and pull down 2.49k, but we verified that it is okay to leave both pull up and pull down open for the pins to be strapped in mode 0. 

    Your understanding above is correct.

    Best,

    J