diff --git a/src/calibrate.rs b/src/calibrate.rs
index 1068669..0decbca 100644
--- a/src/calibrate.rs
+++ b/src/calibrate.rs
@@ -1 +1,150 @@
-pub async fn calibration_loop() {}
+use defmt::Format;
+use embassy_sync::{blocking_mutex::raw::CriticalSectionRawMutex, pubsub::Subscriber};
+use embassy_time::Timer;
+
+use crate::{gcc_hid::GcReport, input::CHANNEL_GCC_STATE};
+
+const CALIBRATION_ENTRY_COMBO: [AwaitableButtons; 4] = [
+    AwaitableButtons::Start,
+    AwaitableButtons::A,
+    AwaitableButtons::X,
+    AwaitableButtons::Y,
+];
+
+/// This doesn't need to be super fast, since it's only used
+/// in calibration mode.
+const BUTTON_POLL_INTERVAL_MILLIS: u64 = 20;
+
+#[derive(Clone, Copy, Debug, Format)]
+enum AwaitableButtons {
+    A,
+    B,
+    X,
+    Y,
+    Up,
+    Down,
+    Left,
+    Right,
+    Start,
+    L,
+    R,
+}
+
+trait WaitForButtonPress {
+    /// Wait for a single button press.
+    async fn wait_for_button_press(&mut self, button_to_wait_for: &AwaitableButtons);
+
+    /// Wait for multiple buttons to be pressed simultaneously.
+    async fn wait_for_simultaneous_button_presses<const N: usize>(
+        &mut self,
+        buttons_to_wait_for: &[AwaitableButtons; N],
+    );
+
+    /// Wait for a single button press of specified buttons, and return the button that was pressed.
+    async fn wait_and_filter_button_press<const N: usize>(
+        &mut self,
+        buttons_to_wait_for: &[AwaitableButtons; N],
+    ) -> AwaitableButtons;
+
+    /// Wait for multiple possible button combinations to be pressed simultaneously, and return the index of the combination that was pressed.
+    async fn wait_and_filter_simultaneous_button_presses<const N: usize, const M: usize>(
+        &mut self,
+        buttons_to_wait_for: &[[AwaitableButtons; N]; M],
+    ) -> usize;
+}
+
+impl<'a, const I: usize, const J: usize, const K: usize> WaitForButtonPress
+    for Subscriber<'a, CriticalSectionRawMutex, GcReport, I, J, K>
+{
+    async fn wait_for_button_press(&mut self, button_to_wait_for: &AwaitableButtons) {
+        loop {
+            if match self.next_message_pure().await {
+                report => is_awaitable_button_pressed(&report, button_to_wait_for),
+            } {
+                break;
+            }
+            Timer::after_millis(BUTTON_POLL_INTERVAL_MILLIS).await;
+        }
+    }
+
+    async fn wait_for_simultaneous_button_presses<const N: usize>(
+        &mut self,
+        buttons_to_wait_for: &[AwaitableButtons; N],
+    ) {
+        loop {
+            if match self.next_message_pure().await {
+                report => buttons_to_wait_for
+                    .iter()
+                    .all(|button| is_awaitable_button_pressed(&report, button)),
+            } {
+                break;
+            }
+            Timer::after_millis(BUTTON_POLL_INTERVAL_MILLIS).await;
+        }
+    }
+
+    async fn wait_and_filter_button_press<const N: usize>(
+        &mut self,
+        buttons_to_wait_for: &[AwaitableButtons; N],
+    ) -> AwaitableButtons {
+        loop {
+            match self.next_message_pure().await {
+                report => {
+                    for button in buttons_to_wait_for {
+                        if is_awaitable_button_pressed(&report, button) {
+                            return *button;
+                        }
+                    }
+                }
+            }
+            Timer::after_millis(BUTTON_POLL_INTERVAL_MILLIS).await;
+        }
+    }
+
+    async fn wait_and_filter_simultaneous_button_presses<const N: usize, const M: usize>(
+        &mut self,
+        buttons_to_wait_for: &[[AwaitableButtons; N]; M],
+    ) -> usize {
+        loop {
+            match self.next_message_pure().await {
+                report => {
+                    for (i, buttons) in buttons_to_wait_for.iter().enumerate() {
+                        if buttons
+                            .iter()
+                            .all(|button| is_awaitable_button_pressed(&report, button))
+                        {
+                            return i;
+                        }
+                    }
+                }
+            }
+            Timer::after_millis(BUTTON_POLL_INTERVAL_MILLIS).await;
+        }
+    }
+}
+
+fn is_awaitable_button_pressed(report: &GcReport, button_to_wait_for: &AwaitableButtons) -> bool {
+    match button_to_wait_for {
+        AwaitableButtons::A => report.buttons_1.button_a,
+        AwaitableButtons::B => report.buttons_1.button_b,
+        AwaitableButtons::X => report.buttons_1.button_x,
+        AwaitableButtons::Y => report.buttons_1.button_y,
+        AwaitableButtons::Up => report.buttons_1.dpad_up,
+        AwaitableButtons::Down => report.buttons_1.dpad_down,
+        AwaitableButtons::Left => report.buttons_1.dpad_left,
+        AwaitableButtons::Right => report.buttons_1.dpad_right,
+        AwaitableButtons::Start => report.buttons_2.button_start,
+        AwaitableButtons::L => report.buttons_2.button_l,
+        AwaitableButtons::R => report.buttons_2.button_r,
+    }
+}
+
+pub async fn calibration_loop() {
+    let mut gcc_subscriber = CHANNEL_GCC_STATE.subscriber().unwrap();
+
+    loop {
+        gcc_subscriber
+            .wait_for_simultaneous_button_presses(&CALIBRATION_ENTRY_COMBO)
+            .await;
+    }
+}