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DP83826I: DP83826 issue

Part Number: DP83826I

Hi team.

We meet some issue using DP83826. Could you please help it?

 

The issue is below.

Now the processor can’t read IP from other the Ethernet nodes. And I think the link hasn’t established.

 

Could you please answer my questions as below?

1. 0x1 register is 0x7849, bit[2] is 0 which means Link not established.

Could you please confirm if it is the hardware issue? Or could also be software issue?

2. For LED0, I think when link is good, LED0 will be high, and when cable is removed, LED0 should be low, am I right?

But from test, I found LED0 is always high. Could you please analysis it?

3. I think the next step should be loopback test. Could you please give the guidance for this debug?

I think after setting registers, we should monitor MAC’s TX and RX signal using Oscilloscope to see the data is same, am I right? Could you please give more details?

4. Registers are attached, appreciate if you can find some useful information to orient the issue.

address 0x0 :0x3100

address 0x1 :0x7849

address 0x2 :0x2000

address 0x3 :0xa130

address 0x4 :0x181

address 0x5 :0x0

address 0x6 :0x4

address 0x7 :0x2001

address 0x8 :0x0

address 0x9 :0x0

address 0xa :0x100

address 0xb :0x0

address 0xc :0x0

address 0xd :0x0

address 0xe :0x0

address 0xf :0x0

address 0x10 :0x4002

address 0x11 :0x108

address 0x12 :0x0

address 0x13 :0x0

address 0x14 :0x0

address 0x15 :0x0

address 0x16 :0x100

address 0x17 :0x41

address 0x18 :0x400

address 0x19 :0x4001

address 0x1a :0x0

address 0x1b :0x7d

address 0x1c :0x5ee

address 0x1d :0x0

address 0x1e :0x102

address 0x1f :0x0


  • Hello,

    To answer your questions:

    1. You are correct, register 1 is showing no link. There could be several causes, we need to narrow down the issue further.

    2. Depending on if LED is pulled high or low, LED may be active low or active high driver.

    3. Loopback test will be a good indicator of if this is an MDI or MII issue. Let's confirm a few other things first.

    4. Register dump shows no active link partner, hence why link may not be established. 

    Before we get into loopback tests, can you confirm the following:

    • RX_CLK frequency
    • Do you see FLPs on the MDI pins after powering up the device?
    • Can you provide a schematic?

    Thank you,

    Nikhil