mcxn236 usb device mode without VBUS

allu — Wed, 17 Jul 2024 12:18:07 GMT

Hi NXP,

We refer NXP SDK_2_14_0_FRDM-MCXN236_rfp USB device example to develop a USB device. However, is it possible to make the USB device mode work without VBUS?

If yes, how can we modify this in the SDK?

Thanks,

Alan

Re: mcxn236 usb device mode without VBUS

diego_charles — Fri, 02 Aug 2024 06:02:11 GMT

Hi @allu

Thank you very much for your patience.

As I reviewed internally, please find below our feedback.

We strongly suggest customers to link MCX N2xx's USB_VBUS pin with USB connector as recommended in our hardware design guide and implemented in the official FRDM-MCX N 236 schematic.

With the USB_VBUS pin detect, the application firmware can easily know if the USB is attached or not.

Leaving USB_VBUS floating is possible, but require the software skip the attach detection, and use a software state machine to check if the USB is linked or not. But we are not sure about the workload to implement this.

Additonally, leaving USB_VBUS disconnect may impact on the USB certification attach and de-attach test, but it will not impact on other test items. As mentioned before, you may use the software approach to solve the attach and de-attach test item issue, but it is not our recommendation.

Anyway, we strongly suggest you to enable the USB_VBUS.

Thank you,

Diego

topic Re: mcxn236 usb device mode without VBUS in MCX Microcontrollers

mcxn236 usb device mode without VBUS

Re: mcxn236 usb device mode without VBUS