Report enter key as pressed when GPIO1 is pulled low

Cargo.toml

@@ -9,3 +9,5 @@ embedded-hal = "0.2.7"
 embedded-time = "0.12.1"
 panic-halt = "0.2.0"
 rp-pico = "0.2.0"
+usb-device = "0.2.8"
+usbd-hid = "0.5.2"

src/main.rs

@@ -1,7 +1,7 @@
 #![no_std]
 #![no_main]
 
-use embedded_hal::digital::v2::OutputPin;
+use embedded_hal::digital::v2::{InputPin, OutputPin};
 
 use embedded_time::fixed_point::FixedPoint;
 
@@ -9,9 +9,16 @@ use panic_halt as _;
 
 use rp_pico::Pins;
 use rp_pico::entry;
-use rp_pico::hal::{Clock, Sio, Watchdog, clocks::init_clocks_and_plls};
+use rp_pico::hal::{Clock, Sio, Watchdog, clocks::init_clocks_and_plls, usb::UsbBus};
 use rp_pico::pac::{CorePeripherals, Peripherals};
 
+use usbd_hid::descriptor::KeyboardReport;
+use usbd_hid::descriptor::generator_prelude::*;
+use usbd_hid::hid_class::HIDClass;
+
+use usb_device::bus::UsbBusAllocator;
+use usb_device::prelude::*;
+
 #[entry]
 fn main() -> ! {
     let mut p = Peripherals::take().unwrap();
@@ -36,13 +43,58 @@ fn main() -> ! {
         &mut p.RESETS,
     );
 
+    let gpio1 = pins.gpio1.into_pull_up_input();
     let mut led = pins.led.into_push_pull_output();
     let mut delay = cortex_m::delay::Delay::new(cp.SYST, clocks.system_clock.freq().integer());
 
+    let usb_bus = UsbBusAllocator::new(UsbBus::new(
+        p.USBCTRL_REGS,
+        p.USBCTRL_DPRAM,
+        clocks.usb_clock,
+        true,
+        &mut p.RESETS,
+    ));
+
+    let mut hid = HIDClass::new(&usb_bus, KeyboardReport::desc(), 127);
+
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x2342, 0x1337))
+        .manufacturer("luj0ga")
+        .product("pico-test")
+        .serial_number("0.1.0")
+        .device_class(3) // HID
+        .build();
+
+    let mut counter = 0;
     loop {
-        led.set_high().unwrap();
-        delay.delay_ms(500);
-        led.set_low().unwrap();
-        delay.delay_ms(500);
+        usb_dev.poll(&mut [&mut hid]);
+
+        if let Ok(key_down) = gpio1.is_low() {
+            let report = if key_down {
+                KeyboardReport {
+                    modifier: 0,
+                    reserved: 0,
+                    leds:     0,
+                    keycodes: [0x28, 0, 0, 0, 0, 0],
+                }
+            } else {
+                KeyboardReport {
+                    modifier: 0,
+                    reserved: 0,
+                    leds:     0,
+                    keycodes: [0, 0, 0, 0, 0, 0],
+                }
+            };
+
+            hid.push_input(&report).ok();
+        }
+
+        if counter == 0 {
+            led.set_high().unwrap();
+        } else if counter == 100 {
+            led.set_low().unwrap();
+        }
+
+        delay.delay_ms(5);
+        counter = (counter + 1) % 200;
     }
 }