The USBD peripheral features a number of dedicated pins.
The dedicated USB pins can be grouped in two categories, signal and power. The signal pins consist of the D+ and D- pins, which connect to the USB host. They are dedicated pins, and not available as standard GPIOs. The USBD peripheral is implemented according to the USB Specification v2.0, 5V Short Circuit Withstand ECN Requirement Change, meaning these two pins are not 5 V tolerant. USB power is supplied on the VBUS pin.
The signal pins and pull-up are operational when the following are true:
- When VBUS is in its valid voltage range
- USBD is enabled through the ENABLE register
For more information about USB power supply and VBUS detection, see USBREG — USB regulator control. For pinout see Pin assignments.