TDA4VM: TDA4VM RGMII TX problem

guo kuo

Part Number: TDA4VM

Hi TI:

The TDA4VM RGMII TX to TC397 RGMII RX.

We test the TXD`s waveform as below.

And we have changed the register below to modify it, however it still does not work.

What can we do to change it?

Thanks!

0 ShreyasRao over 1 year ago

guo,

Trying to understand that the issue here is that the Vol and Voh is not meeting the specs? What is the speed

It seems that the capacitance of the trace is large enough that it is unable to reach the full scale (low and high).

Any schematic available for review? Do you have any series resistors on the traces which can be reduced? What is the trace length?

0 Robert Eschler over 1 year ago in reply to ShreyasRao

How long are the RGMII TX traces? Do you have any in-line/series resistors? Where are you measuring the attached waveform?

Are RGMII traces impedance controlled, solid reference planes, etc?

0 ShreyasRao over 1 year ago

Do you also have waveforms from the TC397 TX to the TDA4VM RX, is there no issue with that? Only with TDAVM TX to TCA RX?

Processors forum