RMII interfaces on iMX93

[Gary_Aylward]

The #iMX93 reference manual describes the RGMII interfaces supporting RMII operation but there is no concrete definition of the pinout of each interface in RMII mode.

Even searching through the pin mapping spreadsheet attached to the reference manual doesn't make it clear where the RMII clock and control signals appear.

Since we are using the iMX93 as an upgrade to a number of existing products we have to use RMII, it is not possible to change all our designs to RGMII.

Where can I find this information please?

[Gary_Aylward]

We are planning to use the Ka-Ro QS93 module which quotes i.MX9352. The Ka-Ro module brings out all the RGMII pins of both Ethernet ports but I can't find out whether the same pins are used when RMII mode is used.

[joanxie]

it seems imx93 doesn't support this so far, only Set eQOS to RGMII mode for 11x11 EVK

https://github.com/nxp-imx/linux-imx/blob/lf-6.1.y/arch/arm64/boot/dts/freescale/imx93-11x11-evk.dts

[Gary_Aylward · Accepted solution]

The iMX93 data sheet, IMX93IEC.pdf, Rev 1 04/2023 says:

Ethernet supports the following key features:

• Support ENET AVB
• Support IEEE 1588
• Support Energy Efficient Ethernet (EEE)
• 1.8V/3.3V RMII operation, 1.8V RGMII operation

I think I've now found the solution buried in the datasheet, although it is not mentioned in the reference manual or the pin mapping spreadsheet attached to the manual.

Sections 4.12.2.1 and 4.12.3.1 define the signal mapping for RGMII and RMII mode for ENET2 and ENET1 respectively.

Hopefully this will be of use to someone else in the future...

[davidpatton]

Thank god for you! Trying to get RMII working with the FEC port has been kicking my butt for weeks and IMX93IEC was the answer!

[joanxie]

yes, for pin mapping, you can refer to the data sheet, I thought you need set up this mode, current bsp doesn't support yet

[joanxie]

which i.mx93evk do you use? 11x11, 9x9 or 14x14? as I known, 14x14 doesn't support RMII so far