4.1.3 USB

The SAM L21 Xplained Pro has a Micro-USB connector for use with the SAM L21 USB module labeled as TARGET USB on the kit. To be able to detect when a target USB cable is connected in self-powered mode, a GPIO is used to detect the VBUS voltage on the connector. In USB host mode VBUS voltage is provided by the kit and can thus not identify a connected device, so another GPIO is used to detect the USB ID of the device.