Hi all
My customer has below questions, please review and comment.
Best regards
Ueli
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We are preparing for compliance testing of the 1000BASE-T1 interface and for this we need to support cable diagnostics.
We tried running the TDR according to the procedure in “snla371a-Configuring for Open Alliance Specification.pdf” and if we connect no cable to the DUT connector we get as result in register TDR_TC12 (0x30F) = 0x71 which means according to Table 7-1 in the datasheet “Cable OK”.
If we connect a cable with ~1.5m to 2m length we get as result 0x161 which means “Open” and a distance of 1m.
The same behavior can be observed for short circuit conditions directly at the connector vs at the cable end.
Thus I have 2 questions:
- Is there some kind of minimum cable length (1m ?) to be connected for the TDR and therefore the cable diagnostics to work properly ?
- Is the fault distance value (bits [13:8] of 0x30F) in meters ? à minimum detection distance is 1m ?
Many thanks and best regards,
