Teensy 4.1 Ethernet adapter | Force speed to 10Mbps

Pfeffer

New member
Hello
I use a Teensy 4.1 with the Ethernet kit.
Does anyone know, how to limit the speed to 10Mbps?
I didn't found anything in the NativeEthernet or QNEthernet lib.

Background:
The Ethernet cable is routed through a robot with rotary feedthrough and various connectors and soldering points.
This connection leads to 10Mbps speed when I connect something over this cabeling to my laptop (result from auto-negotiation). Then the connection works without any problems.
When I connect the Teensy Ethernet adapter to my laptop over this connection and set the Windows Ethernet Adapter to fixed 10Mbps, the Teensy can not be pinnged although the cable link LED is on and the connection is correct. So I think, if the Teensy Ethernet adapter speed would be fixed to 10Mbps it should work.

Summary:
1. Ethernet connection over robot wiring from my laptop to another PC with 10Mbps -> ping OK
2. Ethernet connection over robot wiring from my laptop to the Teensy Ethernet adapter -> ping NOK
3. Direct connection from my laptop to the Teensy Ethernet adapter with 100Mbps-> ping OK
4. Direct connection from my laptop to the Teensy Ethernet adapter with fixed 10Mbps in windows adapter-> ping NOK
 
Last edited:
The Teensy should be able to auto-detect the connection. Some questions:
1. What happens in summary point #1 if the PC is set to 100Mbps? This will indicate whether “over robot wiring” is doing something to the signal.
2. What does “over robot wiring” mean exactly? For example, is there a network switch? A hub? Does it just go into one connector and out another side? Could you show a picture or diagram that illustrates what the connections actually look like?
 
1. Yes the "over robot wiring" is doing something to the signal (Soldering points, connectors, rotary feedthroug). If the PC is set to 100Mbps, there will be no connection.
2. Here a picture of the wiring.
Interesting point:
If i put another switch into the connector-box instead of the ethernet coupler, the connection is set to 100Mbps (per auto-negotiation) and everything is ok.
Anyway it would be helpful if the Teensy can be forced to 10Mbps.
Thank you!
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Pfeffer:
You are aware I hope that Ethernet wires (cat5 and cat6) are controlled impedance wires (twisted pair). You should not use ordinary wires and connectors for Ethernet cabling.
Regards,
Ed
 
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