Going through details and different datasheets/documents, it seems feasible to use two Ethernet interfaces.
But, confusion arise when I checked Toradex pinout designer tool, there is one pin conflicts using two ethernet interfaces on Apalis iMX8 QuadMax module.
I looked at the interface and try designing Ethernet PHY (using AR8031 or KSZ9131), the conflicting pins are optional output pins and could work without it.
Also, when I checked Apalis datasheet (Section 5.3; Page 29), mentions using second ethernet interface using external PHY.
But also states that it is not part of standard Apalis module.
Could you confirm its feasible to use two Ethernet interfaces on Apalis module?
One through available ethernet interface and another through RGMII with PHY.
Hi @shrikrishnabd, how are you?
Welcome to our community !
It is indeed possible to have two Ethernet interfaces on the Apalis iMX8QM. We’re going to send an example of a schematic by e-mail.
The message about not being standard is that if you want to change from Apalis iMX8 to Apalis iMX6 for instance you may stumble into problems.
Thank you. Awaiting example schematic.
Ethernet: !!! on the Apalis IMX8QM
The Ethernet MAC Interface is only supporting 1.8 to 2.5 volts as specified from now on. All the IMX.8 modules that final production ones will only be specified for 1.8 or 2.5.
So your interface on the Ethernet side needs to be not 3.3 volts if you want to use Gbit ethernet. We recommend 1.8 volts.
The secondary Ethernet on the Apalis IMX8 (MAC) is can be switched to 1.8volt or 2.5volt via the device tree. The port of the IMX8 will be switched to 1.8volt.
The MDC and MDIO signal remains at 3.3 volts on the iMX8 side.
So you need level shifting from 3.3 to 1.8 of the Switch since you need to operate the switch at 1.8volt.
The reset should also be shifted to 1.8 volts.
The 22 ohms resistor R27 in the clock line RGMII_REF_CLK should be left away or best up there a 0-ohm resistor
the RGMI1 Interface need also 1.8 Volt pull-ups.
Here a little ref. Schematic with an ethernet PHY.
also we are providing hardware design reviews as a service. Before that you should take advantage of our 30 min personal carrier design call where we give you some tip and tricks.
Thank you, this should help me.
Any chance to get Altium design file for this schematic?
Yes, we would consider utilizing review service, would connect once our design is ready.
Could you help with details on how to get carrier design call?