Implement USB HID device

Cargo.toml

@@ -10,4 +10,6 @@ cortex-m = "0.7.4"
 cortex-m-rt = "0.7.1"
 nb = "1"
 panic-halt = "0.2.0"
-stm32f0xx-hal = { version = "0.18.0", features = ["rt", "stm32f072"] }
+stm32f0xx-hal = { version = "0.18.0", features = ["rt", "stm32f072", "stm32-usbd"] }
+usb-device = "0.2.8"
+usbd-hid = "0.5.2"

src/main.rs

@@ -1,6 +1,6 @@
 /*
  * any key firmware
- * Copyright (C) 2020  Luca Schmid
+ * Copyright (C) 2020-2022  Luca Schmid
 
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -26,6 +26,33 @@ use stm32f0xx_hal::pac::Peripherals;
 use stm32f0xx_hal::prelude::*;
 use stm32f0xx_hal::pwm::tim3;
 use stm32f0xx_hal::timers::Timer;
+use stm32f0xx_hal::usb::{Peripheral, UsbBus};
+use usb_device::prelude::*;
+use usbd_hid::descriptor::KeyboardReport;
+use usbd_hid::descriptor::generator_prelude::*;
+use usbd_hid::hid_class::HIDClass;
+
+enum Action {
+    Copy,
+    Paste,
+}
+
+impl Action {
+    fn as_report(&self) -> KeyboardReport {
+        KeyboardReport {
+            modifier: 1, // Left Ctrl
+            reserved: 0,
+            leds:     0,
+            keycodes: [
+                match *self {
+                    Action::Copy => 0x6, // C
+                    Action::Paste => 0x19, // V
+                },
+                0, 0, 0, 0, 0,
+            ],
+        }
+    }
+}
 
 #[entry]
 fn main() -> ! {
@@ -36,10 +63,13 @@ fn main() -> ! {
     let gpioa = p.GPIOA.split(&mut rcc);
     let gpiob = p.GPIOB.split(&mut rcc);
 
-    let (mut led1_b, mut led1_g, mut led1_r) = cortex_m::interrupt::free(|cs| (
+    let (mut led1_b, mut led1_g, mut led1_r, btn1, usb_dm, usb_dp) = cortex_m::interrupt::free(|cs| (
         gpioa.pa0.into_push_pull_output(cs),
         gpioa.pa1.into_push_pull_output(cs),
         gpioa.pa2.into_push_pull_output(cs),
+        gpioa.pa3,
+        gpioa.pa11,
+        gpioa.pa12,
     ));
 
     led1_r.set_high().ok(); //   0
@@ -62,16 +92,64 @@ fn main() -> ! {
     led2_r.set_duty(led2_r_max); // 0
     led2_g.set_duty(led2_g_max); // 0
     led2_b.set_duty(led2_b_max); // 0
-    // ^ violet
 
     led2_r.enable();
     led2_g.enable();
     led2_b.enable();
 
-    let mut timer = Timer::tim1(p.TIM1, 100.hz(), &mut rcc);
+    let usb = Peripheral {
+        usb: p.USB,
+        pin_dm: usb_dm,
+        pin_dp: usb_dp,
+    };
+    let usb_bus = UsbBus::new(usb);
 
+    let mut hid = HIDClass::new(&usb_bus, KeyboardReport::desc(), 127);
+
+    let mut usb_dev = UsbDeviceBuilder::new(&usb_bus, UsbVidPid(0x2342, 0x1337))
+        .manufacturer("f2o & luj0ga")
+        .product("anykey")
+        .serial_number("v1")
+        .device_class(3) // HID
+        .build();
+
+    let mut timer = Timer::tim1(p.TIM1, 1.khz(), &mut rcc);
+
+    let mut action = Action::Copy;
+    let mut counter = 0;
     let mut hue = 0;
+    let mut prev = false;
     loop {
+        usb_dev.poll(&mut [&mut hid]);
+
+        if counter == 0 {
+            if let Ok(btn1_pressed) = btn1.is_high() {
+                if btn1_pressed != prev {
+                    prev = btn1_pressed;
+
+                    let report = if btn1_pressed {
+                        led1_g.set_low().ok();
+                        action.as_report()
+                    } else {
+                        led1_g.set_high().ok();
+                        KeyboardReport {
+                            modifier: 0,
+                            reserved: 0,
+                            leds:     0,
+                            keycodes: [0, 0, 0, 0, 0, 0],
+                        }
+                    };
+                    cortex_m::interrupt::free(|_| hid.push_input(&report)).ok();
+
+                    if btn1_pressed {
+                        action = match action {
+                            Action::Copy => Action::Paste,
+                            Action::Paste => Action::Copy,
+                        };
+                    }
+                }
+            }
+
             let h_i = hue / 60;
             let f = hue as f32 / 60.0 - h_i as f32;
             let q = 1.0 - f;
@@ -90,6 +168,9 @@ fn main() -> ! {
             led2_b.set_duty(led2_b_max - (led2_b_max as f32 * b) as u16);
 
             hue = (hue + 1) % 360;
+        }
+
+        counter = (counter + 1) % 10;
 
         block!(timer.wait()).ok();
     }