Is USXGMII at 1G compatible with SGMII?

[LukasVik]

Vivado version: 2020.1

Product family: Kintex UltraScale+

IP: Universal Serial XGMII Ethernet Subsystem (1.1)

Reading PG251 and the USXGMII specification, raises the question: Can i connect an USXGMII interface with auto-negotiation to an ethernet interface that only speaks SGMII?

Granted, I have not seen anything that indicates that this would be the case. USXGMII amongst other things seems to use 64/66b encoding even when in 1G mode, which would not work with SGMII (?). But since USXGMII seems to all about compatibility, I figured I would at least ask.

Best regards

Lukas

[ejanney · Accepted solution]

SGMII and USXGMII can not be directly connected.

SGMII is based on 1G 1000BASE-X 8b/10b protocol and does byte duplication to be able to send 10M/100M/1G Ethernet traffic over a 1G 8B10B fixed line rate.

USXGMII is based on 10G BASE-R 64b/66b protocol and does block duplication to be able to send 10M/100M/1G/2.5G/5G/10G Ethernet traffic over a 10G 64b/66b fixed line rate.

[LukasVik]

Hi @ejanney ,

Okay thank you for the information!

Best regards

Lukas