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DP83TG720S-Q1: Hardware Strapping without the need of Software Configuration

Saber Kaygusuz
Prodigy 20 points
Part Number: DP83TG720S-Q1
Other Parts Discussed in Thread: DP83TG720EVM-MC

Tool/software:

Hi Forum,

I'm currently working on a SPE board with the DP83TG720S and DP83867ERGZR PHYs. For testing I have the DP83TG720EVM-MC board to serve as interface to normal Ethernet.

I want my board to be working only using the hardware strappings, with no further software configuration needed.

Here are my strapping configurations of the PHYs.

DP83TG720S:

- MAC Interface = RGMII Align Mode

- MDI Master / Slave = Slave

- Autonomous Disable = Autonomous

- PHY Address = 0x0000

DP83867ERGZR:

- Autoneg. Disable = False

- Autoneg. Select = 100/1000

- RX Clock Skew = 0ns

- TX Clock Skew = 0ns

- Port Mirror Enable = False

- SGMII Enable = False

- PHY Address = 0x0001

I checked all the power supply of the IC's, everything looks fine. Also the clock signal on the DP83TG720S looks good, and the forwarded clock signal to the DP83867ERGZR also looks fine.

Both PHYs seem to be doing something, on the DP83867ERGZR LED0 and LED1 are lighted up, and LED2 blinks sometimes. On the DP83TG720S LED0 is lighted up, and LED1 does nothing. However, I can not manage to establsh a connection with the DP83TG720EVM-MC. I think the Media Converter is plug and play, or are there some further configurations I need to take care of? Also I already checked my board and the strappings multiple times, I don't find any mistake. Am I missing out something?

Thanks for helping.

Yannik

  • 0
    TI__Mastermind 24341 points

    Hello Yannik,

    The lighting of LEDs is a good sign, this indicates that link is established on both sides. 

    The issue is likely on the MAC interface side, I see you have no skew introduced by either DP83TG720 or DP83867. Please select RGMII (TX and RX Shift Mode) on the DP83TG720 via bootstraps. I believe this will resolve the issue. Please let me know the results.

    It should also be noted that for most robust link quality and compliance testing performance, the script given in SNLA371 must be loaded onto the DP83TG720. Basic data transfer can still occur without this.

    Thanks,

    David