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DP83867IS: can't communicate under RGMII mode in DP83867IS

Betty Guo
Expert 7300 points
Part Number: DP83867IS

Hi team,

I have submit E2E question, please see below link:

https://e2e.ti.com/support/interface/f/138/p/810147/3009219#3009219

we have solved the signal voltage level problem, and now the voltage and frequency of signal and clock are normal now, but they still can't communicate using RGMII.

Problem is :

1. CPU sent out 60bit data, but only receive 48bit.

2. CRC check is error.

we think it may software set problem not hardware. One question is about RGMII delay config.

customer set add 0x0086 as below:

bit 7:4       2.75ns ;         bit 3:0     2.25ns

1. Are these delay configuration correct? 

2. Customer use AMC335x or IM.6 platform, could you give reference code about RGMII register configuration base on AMC335X and IM.6, especially delay set?

thank you.

  • 0
    TI__Mastermind 23675 points

    Hi Betty,

    Can you try sending frames that are divisible by 8?

    Right now you are sending odd nibble frames.

    I want to see if this has any factor in the error you are seeing.

    The internal delay you set depends on if you are using any delay at the MAC side or have implemented any delay through the track routing.

    Can you let us know what method(s) you are using?

    2ns delay is best for 1Gbps operation since this gives you the most setup/hold time for RGMII.

  • 0 in reply to Ross Pimentel
    TI__Expert 7300 points

    Hi team,

    You said we can send frames that are divisible by 8, could you give comments that is there any difference between sent frames divisible by 8 and odd nibble frames?

    Do you know which customer use DP83867IS on IM.6 platform? Have you ever seen the similar issue before?

    thank you

  • 0 in reply to Betty Guo
    TI__Mastermind 23675 points

    Hi Betty,

    Frames are sent as octets so there should not be odd nibbles.

    When you are transmitting frames, they should already be divisible by 8. 

    Please check the frames sent out. 

    The DP83867 works with the IM.6 platform.