Hello, is there an know problem with the 1000Base-X autonegotiation in the PCS_PMA unit of the triple speed ethernet mac ? Best regards, Andre

Hi dlim,

my design is in a CYCLONE V SOC, the PCS/PMA block is used to connect the HPS Ethernet MAC ( not the TSE MAC ) to

a fibre or copper SFP. Connections are made using appropriate clock bridges. When a connection can be established

the data exchanges works fine even at high rates so I do not think the problem is here. I have identified the problem

exists only in 1000Base-X mode when autoneg is enabled on both sides. In some cases this connection may work

depending on how tolerant the switch handles autoneg, in some it does not. THE PCS/PMA block is configured to

operate in MAC mode but actually this only applies to SGMII which is causing no problems.

I follow the initialization schemes given in the Manual. Further I have tried all the Erratas I could find about this.

When I disable AUTONEG on both sides the connection can be established without problems in 1000Base-X mode

( 1000Base-T is not affected anyway as it is using SGMII ). I have compiled the design with the latest quartus lite

version 18.1 lite and tried again but the result is the same. Of course I have deleted all the databased and generated

the IP cores with the latest version to rule out there's some old data used in the new compilation then.

Further I have sniffed into the data sent coming out of the 8b10b encoder and sent to the transceiver without finding

abnormal data transmitted. Please see attachment for a screen shot - autoneg sequence starts with /C/ 0x00 as required.

We're abbout to procure a Network tester that allows sniffing the data on the fibre lines and tracking the autoneg process,

I'll get back to you when we have done this. For the time beeing I'll disable the autoneg in 1000Base-X mode and set

the link to fixed speed as a workaround. Of course it would be nice to find out what is really going wrong here.

How shall we proceed, shall we close this case and shall I ask to re-open it when I'm able to do deeper debugging ?

Thanks for for your kind support and for beeing patient with us!

Best regards,

Andre