How to wakeup the nRF52480 on USB power up event from sleep/low power mode?

RE: How to wakeup the nRF52480 on USB power up event from sleep/low power mode?

Jørgen Holmefjord — Thu, 03 Mar 2022 20:38:11 GMT

It is recommended to not enable the USBD peripheral until after the VBUS voltage have been detected. See USBD power-up sequence.

RE: How to wakeup the nRF52480 on USB power up event from sleep/low power mode?

tordown97 — Tue, 01 Mar 2022 15:19:19 GMT

Hi,

Yes I need to go back to __WFE after a status LED is lit if the USB is plugged in and I want to avoid a chip reset.

Also, to make nrf_drv_power_usbevt_init() to capture NRFX_POWER_USB_EVT_DETECTED the USB peripheral should be enabled before entering the __WFE right?

Thanks

RE: How to wakeup the nRF52480 on USB power up event from sleep/low power mode?

Jørgen Holmefjord — Tue, 01 Mar 2022 14:54:43 GMT

Hi,

Do you require the device to stay in System ON/__WFE mode? It is possible to wake the chip from the lowest power mode (System OFF) by both GPIO and from detecting a valid USB voltage on the VBUS pin. Wakeup from System OFF will cause the chip to reset, and you need to do any initialization again. See USB supply for more information about how this works.

If you want to stay in System ON mode, the method you describe would be the best option.

Best regards,
Jørgen