+#![no_std]
+#![no_main]
+
+use panic_halt as _;
+use feather_m0 as hal;
+use hal::entry;
+
+use hal::clock::GenericClockController;
+use hal::pac::{interrupt, CorePeripherals, Peripherals};
+
+use hal::usb::UsbBus;
+use usb_device::bus::UsbBusAllocator;
+
+use usb_device::prelude::*;
+use usbd_serial::{SerialPort, USB_CLASS_CDC};
+
+use cortex_m::asm::delay as cycle_delay;
+use cortex_m::peripheral::NVIC;
+
+#[entry]
+fn main() -> ! {
+ let mut peripherals = Peripherals::take().unwrap();
+ let mut core = CorePeripherals::take().unwrap();
+ let mut clocks = GenericClockController::with_internal_32kosc(
+ peripherals.GCLK,
+ &mut peripherals.PM,
+ &mut peripherals.SYSCTRL,
+ &mut peripherals.NVMCTRL,
+ );
+ let mut pins = hal::Pins::new(peripherals.PORT);
+ let mut red_led = pins.d13.into_open_drain_output(&mut pins.port);
+
+ let bus_allocator = unsafe {
+ USB_ALLOCATOR = Some(hal::usb_allocator(
+ peripherals.USB,
+ &mut clocks,
+ &mut peripherals.PM,
+ pins.usb_dm,
+ pins.usb_dp,
+ &mut pins.port,
+ ));
+ USB_ALLOCATOR.as_ref().unwrap()
+ };
+
+ unsafe {
+ USB_SERIAL = Some(SerialPort::new(&bus_allocator));
+ USB_BUS = Some(
+ UsbDeviceBuilder::new(&bus_allocator, UsbVidPid(0x16c0, 0x27dd))
+ .manufacturer("Fake company")
+ .product("Serial port")
+ .serial_number("TEST")
+ .device_class(USB_CLASS_CDC)
+ .build(),
+ );
+ }
+
+ unsafe {
+ core.NVIC.set_priority(interrupt::USB, 1);
+ NVIC::unmask(interrupt::USB);
+ }
+
+ // Flash the LED in a spin loop to demonstrate that USB is
+ // entirely interrupt driven.
+ loop {
+ cycle_delay(15 * 1024 * 1024);
+ red_led.toggle();
+ }