RMII just means it uses fewer I/O pins from the MCU as compared to MII. I
don't remember the details either but it's possible that some chips support
RMII and not MII because they don't have the additional I/O pins.
Tiva-C (arch/arm/src/tiva) supports RMII (the chip has the built-in MAC and
PHY) so maybe you can use that as a general example. Of course the details
of drivers for STM32 will be quite different.
Cheers
Nathan
On Thu, Feb 29, 2024 at 2:15 PM Alan C. Assis wrote:
> Hi Roland,
>
> We had a discussion about it a few months ago!
>
> We know it is possible, but nobody until now tried to do it.
>
> Basically you will need RMII support on both chips, I don't remember the
> details why MII will not work (or will be more difficult to work)
>
> There is a discussion about it here, maybe you can get more insights:
>
> https://stackoverflow.com/questions/39503466/can-two-ethernet-mac-chips-be-connected-directly-without-going-thru-phy
>
> Best Regards,
>
> Alan
>
>
> On Thu, Feb 29, 2024 at 2:11 PM Roland wrote:
>
> > Hi,
> >
> > I would like to directly connect a STM32F7 processor running Nuttx, to an
> > external MCU (i.e., NXP imx8m) through RMII directly, without the need
> for
> > PHY IC in between.
> > Is this supported by Nuttx? I checked into the documents but this direct
> > mode seems not been mentioned anywhere.
> > Can anyone please confirm if this is supported, or I have to change
> > something by myself?
> >
> > Thank you.
> >
> > /Roland
> >
> >
>
