DP83826E: Unable to communicate

Hi Rhea,

Could you also provide the working measured waveforms with the waveforms labeled as well as registers 0x00-0x1E, 0x467, 0x468?

Best regards,

Melissa

Hi Melissa,

The required information is updated in the attachment.

DP83826E_20230512.docx

Many thanks!

Hi Rhea,

Looking at the register dump, it looks like 0x0005 = 0, meaning that the link partner is not advertising 100Base-TX Full-Duplex Support, let alone any speeds.

Please ask the customer to check their link partner configuration.

One test they can try to make sure the PHY works is to connect two of their DP83826 PCBs together and seeing if they link through register 0x0001[2].

Best regards,

Melissa

Hi Melissa,

1. Remove the transformer T1. Connect TD_P, TD_M, RD_P, and RD_M of chip U7 (DP83826E) on the two control boards in pairs (TD_P1- RD_P2, TD_M1-RD_M2, RD_P1-RD_P2, RD_M1-TD_M2). Register 0x0001[2] is zero.

2.  Single chip using register loop performance is impassable, 16h register after 4 bits write 5, read data after 4 bits or 5, and the penultimate 5 is 0 or 1 result.

Thanks!

Hi Rhea,

Could you try keeping T1 and connecting the boards? Could you provide a reg dump for when the boards are connected to each other?

Did you also check their link partner configuration in the original setup?

Best regards,

Melissa

Hi Melissa,

1. The following is the value of one of the registers after the two DP83826 are connected.

2. The following is the waveform detected on the network cable：

Many thanks!

Hi Rhea,

Why is the customer pulling up the MDI lines?

Would you be able to try this configuration from the datasheet instead?

Best regards,

Melissa

Hi Melissa，

The client is doing loopback test, but it still fails. Data is sent at the MAC layer of the chip, but no data is returned at the chip end of 83826.

Attached is the whole process and record of the test.

Loop test record_20230525.docx

Please help to support this case,many thanks~

Hi Rhea,

Did your customer try the new configuration I suggested above? The MDI lines should not be pulled up.

Best regards,

Melissa

Hi Melissa，

The customer has modified the schematic diagram as required.  Updated design and testing information is attached.

DP83826ERH_Design and test updates_20230528.docx

Please help to suggest, thank you!

Hi Rhea,

Thank you for providing this information - Could you please summarize what the issue the customer is currently seeing now (is it the same issue as before)? The document attached is quite long and I'm not sure exactly what issue I am diagnosing.

Best regards,

Melissa