• Resolved

Linux/DP83822HF: DP83822HF FX Not working.

Part Number: DP83822HF

Tool/software: Linux

Hi.

I'm using AM572x custom board

and, DP 83822HF is connected to RPU2 ETH0/ETH1

I have question.

Q1. GENCFG(0x465) "phy_read" value is invalid.

        The value does not changed when i set  "phy_write(phydev, 0x465, 0x1);"

==== DP83822HF_read_status 761===
BMCR(0x0): 0x3100
BMSR(0x1): 0x7849
PHYIDR1(0x2): 0x2000
PHYIDR2(0x3): 0xa240
CR1(0x9): 0x0
CR2(0xa): 0x4100
PHYSCR(0x11): 0x4100
RCSR(0x17): 0x41
LEDCR(0x18): 0x400
PHYCR(0x19): 0x21
GENCFG(0x465): 0xffffffea
=================

Q2. DP83822HF Reg value is correct.
       But, I don't know why FX not working.

Best Regards

John

  • In reply to Rob Rodrigues:

    I don't know SFP module signal.
    and
    i want to know wave signal about SFP module between phy(TD+, TD- , RD+, RD-).

    Best Regards
    John
  • In reply to Yohan Kim:

    Hi John,

    One of your problems may be your SFP has a LOS signal. In the diagram you posted earlier in the thread, the SFP shows a LOS or loss of signal pin. The DP83822HF supports a SD pin or signal detect.

    The LOS output from your SFP must be inverted to provide the proper SD input to the DP83822HF to indicate a link is available across fiber. You can do this by changing bit[0] in register 0x465 to 1.

    Also, which mode are you strapping the RX_ER pin to?

    Best Regards,

    Rob Rodrigues

    EFL (Ethernet & FPD Link) Applications Engineer

  • In reply to Rob Rodrigues:

    Hi Rodrigues,

    The LOS output from your SFP must be inverted to provide the proper SD input to the DP83822HF to indicate a link is available across fiber
    -> I already doing it.

    You can do this by changing bit[0] in register 0x465 to 1.
    -> I tried both. (changed bit[0] in register 0x465 to 1 or 0.)
    -> But, FX not working

    Also, which mode are you strapping the RX_ER pin to?
    -> I used RX_ER pin mode 1. It is RGMII_EN '0' and SD_DIS '0'.


    Best Regards,
    John
  • In reply to Rob Rodrigues:

    Hi Rodrigues,

    I have question.

    DP83822HF is not PECL.
    However, most SFP modules are PECL type.

    What type of module should I use?

    Best Regards,
    John
  • In reply to Yohan Kim:

    Hi John,

    It does not matter that the 822 is a current mode line driver and that most SFPs are PECL.
    This is why you have DC blocking capacitors. Please see the example diagram in the DP83822HF datasheet.
    You will see that we recommend 0.1uF DC blocking caps.

    Kind regards,
    Ross
  • In reply to Ross Pimentel:

    Thnak you for your reply.

    I solved the problem.

    The problem was that phy addr were '0' both.. (PRU2-0 ADDR:0 / PRU2-1 ADDR:0)

    It was my mistake.

    Best Regards,
    John Kim