topic MCXA153VLF external Crystal Oscillator in MCX Microcontrollers

MCXA153VLF external Crystal Oscillator

_Ferrari_ — Mon, 16 Jun 2025 14:59:39 GMT

Dear all,

I'm developing a project based on the MCXA153VLF CPU. The device requires an external crystal oscillator. Unfortunately, all the example projects I've found are configured for the FRO oscillator. I'm struggling with how to either convert these projects or create a new one from scratch and correctly configure the external crystal using the MCXpresso clock config tool.

Has anyone encountered a similar issue? How did you resolve it?

Thank you very much for your help and cooperation.

Regards,

Re: MCXA153VLF external Crystal Oscillator

EdwinHz — Fri, 20 Jun 2025 21:18:22 GMT

Hi @_Ferrari_,

You can setup an external oscillator for the MCXA153 by going into ConfigTools and Clocks. Then on the diagram window, simply right click on the SOSC and click "Enable SCG.SOSC". A window will open where you can set up the frequency of your external clock:

Make sure that on the Clocks Table window you set the External Reference Mode to Crystal oscillator:

Then in Pins Tool, simply add the XTAL and EXTAL pins as the SCG0 function and you'll be set:

BR,
Edwin.