diff --git a/Cargo.lock b/Cargo.lock
index 4c79be1..4853d4c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -26,6 +26,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "bitflags"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+
 [[package]]
 name = "cfg-if"
 version = "0.1.10"
@@ -50,6 +56,7 @@ name = "gamebridge"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "bitflags",
  "log",
  "pretty_env_logger",
 ]
diff --git a/gamebridge/Cargo.toml b/gamebridge/Cargo.toml
index 5f31f62..155c798 100644
--- a/gamebridge/Cargo.toml
+++ b/gamebridge/Cargo.toml
@@ -8,5 +8,6 @@ edition = "2018"
 
 [dependencies]
 anyhow = "1.0"
+bitflags = "1.2"
 log = "0.4"
 pretty_env_logger = "0.4"
diff --git a/gamebridge/src/controller.rs b/gamebridge/src/controller.rs
new file mode 100644
index 0000000..d0b0e6b
--- /dev/null
+++ b/gamebridge/src/controller.rs
@@ -0,0 +1,86 @@
+bitflags! {
+    // 0x0100 Digital Pad Right
+    // 0x0200 Digital Pad Left
+    // 0x0400 Digital Pad Down
+    // 0x0800 Digital Pad Up
+    // 0x1000 Start
+    // 0x2000 Z
+    // 0x4000 B
+    // 0x8000 A
+    pub(crate) struct HiButtons: u8 {
+        const NONE = 0x00;
+        const DPAD_RIGHT = 0x01;
+        const DPAD_LEFT = 0x02;
+        const DPAD_DOWN = 0x04;
+        const DPAD_UP = 0x08;
+        const START = 0x10;
+        const Z_BUTTON = 0x20;
+        const B_BUTTON = 0x40;
+        const A_BUTTON = 0x80;
+    }
+}
+
+impl HiButtons {
+    pub fn clear(&mut self) {
+        self.bits = 0;
+    }
+}
+
+bitflags! {
+    // 0x0001 C-Right
+    // 0x0002 C-Left
+    // 0x0004 C-Down
+    // 0x0008 C-Up
+    // 0x0010 R
+    // 0x0020 L
+    // 0x0040 (reserved)
+    // 0x0080 (reserved)
+    pub(crate) struct LoButtons: u8 {
+        const NONE = 0x00;
+        const C_RIGHT = 0x01;
+        const C_LEFT = 0x02;
+        const C_DOWN = 0x04;
+        const C_UP = 0x08;
+        const R_BUTTON = 0x10;
+        const L_BUTTON = 0x20;
+    }
+}
+
+impl LoButtons {
+    pub fn clear(&mut self) {
+        self.bits = 0;
+    }
+}
+
+pub(crate) fn test(st: crate::MTState) {
+    let mut lo: LoButtons = LoButtons::NONE;
+    let mut hi: HiButtons = HiButtons::NONE;
+
+    loop {
+        use std::{thread::sleep, time::Duration};
+        let one_second = Duration::new(1, 0);
+
+        hi = HiButtons::A_BUTTON | HiButtons::START;
+
+        {
+            println!("pressing a + start");
+            let mut data = st.write().unwrap();
+            data.controller[0] = hi.bits as u8;
+            data.controller[1] = lo.bits as u8;
+        }
+
+        sleep(one_second);
+
+        hi.clear();
+        lo.clear();
+
+        {
+            println!("releasing a + start");
+            let mut data = st.write().unwrap();
+            data.controller[0] = hi.bits as u8;
+            data.controller[1] = lo.bits as u8;
+        }
+
+        sleep(one_second);
+    }
+}
diff --git a/gamebridge/src/main.rs b/gamebridge/src/main.rs
index d91f73c..12410d9 100644
--- a/gamebridge/src/main.rs
+++ b/gamebridge/src/main.rs
@@ -1,20 +1,51 @@
+#[macro_use]
+extern crate bitflags;
+
+pub(crate) mod controller;
+
 use anyhow::{anyhow, Result};
 use log::{debug, error, info, warn};
 use std::{
     fs::{File, OpenOptions},
     io::{Read, Write},
     str::from_utf8,
+    sync::{Arc, RwLock},
+    thread::spawn,
+    time::Instant,
 };
 
+#[derive(Debug)]
+pub(crate) struct State {
+    controller: [u8; 4],
+    last_got: Box<Instant>,
+    ok: bool,
+}
+
+pub(crate) type MTState = Arc<RwLock<State>>;
+
 fn main() -> Result<()> {
     pretty_env_logger::try_init()?;
-    let mut controller_data = [0; 4];
 
     let mut vblank = File::open("vblank")?;
     let mut input = OpenOptions::new().write(true).open("input")?;
 
+    let st = {
+        let st = State {
+            controller: [0; 4],
+            last_got: Box::new(Instant::now()),
+            ok: true,
+        };
+
+        Arc::new(RwLock::new(st))
+    };
+
     info!("ready");
 
+    {
+        let st = st.clone();
+        spawn(move || controller::test(st));
+    }
+
     loop {
         let mut data = [0; 3];
         debug!("waiting for vblank");
@@ -23,11 +54,14 @@ fn main() -> Result<()> {
         debug!("got data: {}", str);
 
         match str {
-            "OK\n" => input.write(&controller_data)?,
+            "OK\n" => {
+                let data = st.read().unwrap();
+                input.write(&data.controller)?
+            }
             "BYE" => {
                 warn!("asked to exit by the game");
                 return Ok(());
-            },
+            }
             _ => {
                 error!("got unknown FIFO data {}", str);
                 return Err(anyhow!("unknown FIFO data received"));