Part Number: DS250DF230
Goodday
Just some background, I have setup the chip to a bitrate of 10.31250 Gbps for 10GBASE-R.
I am able to send and receive 10G traffic through the device with no errors and the CDR is reporting a lock. So all is well at 10G.
1st question) I then run 5GBASE-R traffic through the device, which is exactly half of the bit rate of 10G. In this case, the CDR also reports a lock, even though the bitrate is set to 10.31250 Gbps. Packets also pass through with no errors. Is it expected that the CDR will still lock at exactly half the set bitrate?
Following this I have also sent 2.5GBASE-X traffic through the device. To do this I enable the Raw Bypass mode (using Register 0x1e) when the CDR is not locked.
At this point I would see continuous packet errors during a 2.5G packet test (about 1% of the traffic). After some time testing different settings I found that if I set the adapt mode to no adapt (register 0x31), the errors would stop and all of the traffic would pass with no errors. The adapt mode was set to 1 before changing this setting, as part of the Backplane/midplane setup of the programmers guide.
2n question) Can you explain why 2.5G traffic would have errors when the CTLE only adapt mode was active, and then 0 errors when the adapt mode is deactivated? Does this make sense at all to you?
Any help would be much appreciated.
