At room temperature, after successful chain construction, the signal is cooled down to low temperature. When the signal reaches -25℃, CRC and port down/up will appear on corresponding ports.
Structure: MAC<- >Re-timer<- > Port
In case of problems, by reading 0x27 and 0x28 , it is found that the eye height and eye width of the signal received by re-timer become small... However, when something goes wrong, the CDR of the corresponding port will be reset and can be back to normal.
My question:
1. What cause this effect, is there a temperature limit?
2. From which register that I could read the current status of CTLE?
Thanks.