USB_DeviceSetSpeed() fix for usb_device_descriptor.c

Don_Adams_HPE — Mon, 13 Apr 2026 22:03:35 GMT

We found a problem in the usb_device_descriptor.c file of the frdmmcxn947_dev_phdc_weighscale_freertos_cm33_core0 sample project for the FRDM-MCXN947 development board. We used this project as the basis for a new project. After an upgrade to MacOS version Tahoe 26.4 our USB communication stopped working. The symptom of the problem was that communication from the Mac to the FRDM-MCXN947 development board worked, but communication from the development board back to the Mac stopped working. The fix to the problem was the following code changes to the USB_DeviceSetSpeed() function in usb_device_descriptor.c:

- if (((pDescStart->endpoint.bEndpointAddress & USB_DESCRIPTOR_ENDPOINT_ADDRESS_DIRECTION_MASK) ==
+ if (((pDescStart->endpoint.bmAttributes & USB_DESCRIPTOR_ENDPOINT_ATTRIBUTE_TYPE_MASK) ==
+ USB_ENDPOINT_INTERRUPT) &&
+ ((pDescStart->endpoint.bEndpointAddress & USB_DESCRIPTOR_ENDPOINT_ADDRESS_DIRECTION_MASK) ==

- else if (((pDescStart->endpoint.bEndpointAddress & USB_DESCRIPTOR_ENDPOINT_ADDRESS_DIRECTION_MASK) ==
+ else if (((pDescStart->endpoint.bmAttributes & USB_DESCRIPTOR_ENDPOINT_ATTRIBUTE_TYPE_MASK) ==
+ USB_ENDPOINT_BULK) &&
+ ((pDescStart->endpoint.bEndpointAddress & USB_DESCRIPTOR_ENDPOINT_ADDRESS_DIRECTION_MASK) ==

We no longer have problems with USB communication. I am posting this information in case it solves USB communication problems for others as well.

Re: USB_DeviceSetSpeed() fix for usb_device_descriptor.c

Alice_Yang — Wed, 15 Apr 2026 10:24:58 GMT

Hi @Don_Adams_HPE

Thank you for your kind sharing.
I will report this to the internal SDK team for further review.
Thank you.

Alice

MCX MicrocontrollersのトピックUSB_DeviceSetSpeed() fix for usb_device_descriptor.c

USB_DeviceSetSpeed() fix for usb_device_descriptor.c

Re: USB_DeviceSetSpeed() fix for usb_device_descriptor.c