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DP83867IS: Quetions Regarding Compliance Testing

Darren (FAE)
Expert 5483 points
Part Number: DP83867IS


I am supporting a design using the DP83867IS; the board is undergoing compliance testing.
The "Peak Output Voltage" Test is coming back "FAIL". (Seems the amplitude is a little too low - see attached results)

The testing follows the TI Literature on Measurement Setup for Compliance Testing (SNLA239B)
As stated in the document:

PROG_GAIN(0x01D5) UNF_FUNC_MODE = 1

1) Do you have any thoughts on what's happening?

2) Is there a register to control the MDI Output Gain?
(Something like the IO_IMPEDANCE_CTRL for the RGMII)

3) Can the MDI Output Gain be modified by using PROG_GAIN(0x01D5)?

Regards,
Darren

  • 0
    TI__Mastermind 25955 points

    Hi Darren,

    Could you share the schematics of your design. We want to double on your MDI connection.

    Could you also try the compliance test in the following script to test it out and let me know the result? Here is the script:

    • Reg 0x001F = 0x8000 //reset PHY
    • Reg 0x0000 = 0x0140 //1000 Base-T Mode
    • Reg 0x0010 = 0x5008 //forced MDI Mode
    • Reg 0x0009 = 0x3B00 //Test Mode 1
    • Reg 0x0025 = 0x0480 //output test mode to all channels

    --

    Regards,
    Hillman Lin

  • 0 in reply to Hillman Lin
    TI__Expert 5483 points

    Tried running the tests with the register settings as described in the above post.
    Still unable to pass...

    Actually, compared with when Reg 0x01D5 = 0xF508 the amplitude was even lower...

    Is there a register setting for the below feature?
    - A register than can set the MDI output gain? (Like the RGMII's IO_IMPEDANCE_CTRL register)
    - Is it possible to use PROG_GAIN(0x01D5 to set the MDI output gain?

    Confirming internally to see if schematics can be provided; or to what level of detail...

    Regards,
    Darren

     

  • 0 in reply to Darren (FAE)
    TI__Mastermind 25955 points

    Hi Darren,

    Could you also ask the customer to see rather they are able to read the register 0x01D5 when they write it to 0xF508. Is customer using the extended register library when they write the register 0x01D5?

    I will wait the the response for the schematic for the MDI side of the PHY.

    --

    Regards,

    Hillman Lin