topic Re: MX8MP ENET voltage in MCX Microcontrollers

MX8MP ENET voltage

mmagargee — Fri, 16 Oct 2026 13:15:09 GMT

Hello,

We are migrating from an MX8X controller to MX8MP. In the older one, ENET0 and ENET1 supported voltage 1.8V, 2.5V, 3.3V (RMII all three, RGMII first two only).

MX8MP removes the 2.5V option, but allows 1.8V and 3.3V choices. Absolute Vmax is 3.8V. The question is, what happens in a 2.5V operation on NVCC_ENET? 2.5 will not exceed the absolute max. But how are the MAC signals configured and what kind of impact would 2.5V operation have long term?

I ask because it would be great to avoid updating the older PHY that is currently running both its supply and VDDIO on 2.5V.

Thank you,

Mike

Re: MX8MP ENET voltage

JorgeCas — Fri, 16 Oct 2026 18:40:07 GMT

Hello,

As mentioned in the documentation, the interface supports only two voltage levels, 1.8 V and 3.3 V. Even if 2.5 V is within the overall operating voltage range, 2.5 V signals may not meet the specified thresholds for valid logic levels, which could result in unpredictable behavior.

I recommend using either 1.8 V or 3.3 V for this interface.

Best regards.

Re: MX8MP ENET voltage

mmagargee — Fri, 16 Oct 2026 21:36:12 GMT

Thank you, Jorge. Love the avatar.