DS125DF1610: DS125DF1610 Application Question

Hi Qiang,

Qiang Ren said:

When doing CDR reset, does it reset the CTLE and DFE parameters? Or only relock the CDR?

When using default settings, both CTLE and DFE will re-adapt when CDR is reset, as adaptation occurs during lock acquisition.

Note that DFE is disabled by default. The programming guide includes instructions on how to enable the DFE.

Qiang Ren said:

When CDR unlocks due to some issue like signal integrity, is it possible to relock CDR in case that the input signal is always there?

Yes, CDR will continually attempt to lock when signal detect is present.

Qiang Ren said:

Is there register to configure the CDR bandwidth?

Please refer to this e2e thread where Rodrigo explained how to configure CDR bandwidth.

https://e2e.ti.com/support/interface-group/interface/f/interface-forum/597493/ds125df1610-how-to-improve-jitter-tolerance/2315856?tisearch=e2e-sitesearch&keymatch=ds125df1610%252520AND%252520%252522cdr%252520bandwidth%252522#2315856

Qiang Ren said:

Is there a register to configure the loop back path: TX->RX and RX->TX?

It is not possible to loopback channel outputs to channel inputs internally. It is possible to reconfigure which channel inputs route to which channel outputs within each quad using the cross point feature.

Please let me know if the customer is interested in using the crosspoint. I can provide a detailed description on crosspoint register settings as the instructions in the programming guide are somewhat ambiguous.

Qiang Ren said:

For Item 3&4, I couldn't find the register in the programming guide. If you got latest programming guide to support that, can you share with us? 

The programming guide hasn't been updated since August 2014. Please let me know if this is not the version you have.

Best,

Lucas