RevMII on the i.MX RT1180

[NicholasWatt]

Hi there,

I am currently implementing a design where an i.MX-RT1180 will communicate with a secondary microcontroller over RMII without PHYs (MAC to MAC). From what I can gather from the reference manual, reverse mode (RevMII) on the NETC switch controller allows the RT1180 to act as a virtual PHY to the other MAC, however I am unable to find guidance on whether the RMII signals should be connected in a PHY to MAC (Tx to Tx, Rx to Rx) or in a MAC to MAC configuration (Tx and Rx crossed). Any help on the matter would be greatly appreciated

Many Thanks

[NicholasWatt]

Hi @Gavin_Jia 

Thankyou for your response. I think I am going to connect it in a MAC-to-MAC configuration with the management interface connected to the appropriate RevMII management pins. Ill use 0R resistors on the RMII such that I can change the order if it doesn't work.

Best Regards

[Gavin_Jia]

Hi @NicholasWatt ,

Thanks for your interest in NXP MIMXRT series!

The solution you mentioned is totally feasible in theory, but since the SDKs are all based on EVK, there is no official implementation or guidance on it at the moment. Sorry for that.

I've checked the forums for customers who have implemented similar solutions, so maybe checking this thread will be of some help to you: https://community.nxp.com/t5/i-MX-RT-Crossover-MCUs/Ethernet-MAC-to-MAC-i-MX-RT-1020/m-p/990715

Best regards,
Gavin