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DP83867IR: DP83867 compatibility issue

Part Number: DP83867IR

Hi Team,

My customer using DP83867IR for IPCAM Gigabit Phy and meet two issues,

1. How to confirm our compatibility?

Customer connect DP83867 to 100/10M PC and config DP83867 as Autoneg, DP83867 identify this conection as 1G speed and can not connect. if change PC setup to 100M Full-Duplex than start to connect.

2. How to fine tune RMII timing? do we have SOP?

Thanks & Regards

Eddie

  • Hi Eddie,

    1. If the DP83867 is resolving to 1G connection, the link partner is indicating it is capable of 1G. What compatibility needs to be confirmed? The full way to guarantee an Ethernet PHY is functioning properly is doing compliance testing. To do this compliance testing, however, it requires specialized software on an oscope. If this is available, this would be best.

    2. I believe you mean RGMII timing. We do not provide an SOP, but generally RGMII timing uses the default setting which places the clock at the mid-point in the data. This is usually OK because the rising and falling edge rates are very similar in time.

    Best Regards,
  • Hi Rob

    Compatible issue is below

    Customer's IPCAM use DP83867 and connect with a 100/10 PC network card
    But DP83867 speed show working on 1Gbps

    1. May I know if compliance test is pass ,this result could solve compatible issue ?
    2. If compliance test is pass ,do I need to check RGMII timing ??

    I mean if I want to make sure what test we need to do and can prove DP83867 's function have no problem

    BTW. Our customer use DP83867 RGMII default setting ,but DP83867 can't link with PC network card
  • Hi Kai,

    Read register 0xA from the DP83867 when it resolves to 1G operation. If bit[11] or bit[10] on the DP83867 is set, then it means the PC network card is telling the DP83867 it is capable of 1G operation.

    That means the issue is not DP83867 but is the network card.

    Also do you have a schematic for the DP83867 IPCAM is using?

    1. It is difficult to say if compliance will cause an auto-negotiation error. The problem you are describing is an auto-negotiation error. This is usually caused by reflections or other problems on the cable.
    2. Compliance testing applies only to the cable, not RGMII. RGMII timing is usually measured on HW to determine if it meets the RGMII spec.

    Best Regards,
  • HI Rob

    Schematic as attached file 

    Original design is using KSZ9031 

    1. We test 2~3pcs PC network card and one of network card have this issue ,but we use KSZ9031 to test this network card ,it will not have this issue 

    2. We use RGMII default delay timing ,System can't detect network card (MDIO can communication normally) ,when we reduce delay time to 0.25nS

    DP83867 can detect network card ,This platform use Ambarella S5L ,may I know what's the delay time value is correct ?

    I saw a document "RGMII Interface Timing Budgets" ,but not have how to measurement detail 

    1805.DP83867 schematic.pdf

    www.ambarella.com/.../S5L-Product-Brief.pdf

  • Hi Kai,

    The schematic looks good. I have 1 suggestion which is to strap the RX_CTRL pin to mode 3. This can possibly cause some auto-negotiation problems if RX_CTRL is strapped into mode 1.

    1. Your problem does not sound similar to it, however. We should really look at DP83867IR register 0xA to determine if the connected PC is telling the DP83867 it is capable of 1000BASE-T capability. This could be a problem with the PC card, even if KSZ9031 can detect the issue. Please provide a register dump of the DP83867 from register 0x0 to 0x1f when connected to the PC card with a problem.

    2. The delay time should not be set to 0.25ns. RGMII needs some delay between CLK and Data signals. The delay is optimally 2ns when measured at the receiver. The RGMII timing budget app note does not include how to make the measurement.

    The measurement should be made at the receiver or transmitter based on which parameter of the RGMII spec you are validating. The RGMII spec has limits for both the receiver and transmitter.

    In the case of the PHY, it is the transmitter of the RX_CLK, RXD[3:0], and RX_CTRL signals.

    In the case of the MAC, it is the transmitter of the TX_CLK, TXD[3:0], and TX_CTRL signals.

    The measurement should be done with a sufficiently high BW scope. I recommend 500MHz or higher.

    Best Regards,