Arria 10 XVCR oversampling 155Mbps CDR setting

Hi Penn,

I have consulted internal team further on oversampling operation.

Below is the design guideline.

• Oversampling support can be achieved using CDR LTR manual mode + additional soft CDR logic design
• CDR must not be set to LTD mode in low data rate mode (<1Gbps) as it may loose lock due to nature architecture design to serve higher data rate transmission only
• However the issue with using LTR mode is it's not really generating real recover clock from incoming Rx data anymore hence the data phase maybe difference. Additional soft CDR logic design is required to take care of this issue. I believe your customer design is lacking of this soft CDR logic
• Attached is one of the oversampling reference design design that you can share with customer as reference

Thanks.

Regards,

dlim