Tim Zuercher

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10 years, 6 months ago.

EthernetInterface trouble with Gigabit Switch

Hello,

I am trying to get the mbed to talk to my computer through a gigabit ethernet switch from B&B electronics (EIR408-T). I am getting an intermittent connection. Monitoring the LED_LINK pin I get a high until shortly after the cable is plugged, then it goes low followed by the system connecting and starting to send packets. Before any packets are sent the LED_LINK signal goes high again indicating that the link was lost.

When I connect the mbed directly to my computer or to a NetGear gigabit router (GS105) everything works fine. The signal goes low, the system connects and sends packets while the signal stays low. I have tried manually setting the link to 100Base-TX Full duplex (which is the same as what auto negotiate results in) to no avail.

Anybody have any ideas?

Thanks,

Tim

This can be solved by disabling auto negotiation and setting speed to 10MBps. Auto negotiation does not appear to work with some switches.

posted by Tim Zuercher 16 Mar 2016

1 Answer

Earl Manning
6 years, 3 months ago.

Hello Tim,

Thank you for posting the solution. I am going to copy it here into the "Answer" section.

Quote:

This can be solved by disabling auto negotiation and setting speed to 10MBps. Auto negotiation does not appear to work with some switches.

posted by Tim Zuercher 16 Mar 2016

Thank you, - Earl, team Mbed