diff --git a/src/emulator/system/emulator.rs b/src/emulator/system/emulator.rs
index a35b3bc..7e06394 100644
--- a/src/emulator/system/emulator.rs
+++ b/src/emulator/system/emulator.rs
@@ -1,6 +1,6 @@
 use std::{
     sync::{
-        Arc, Mutex,
+        Arc, Mutex, MutexGuard,
         mpsc::{self, Receiver, Sender},
     },
     thread,
@@ -15,27 +15,39 @@ use crate::{
     },
 };
 
-pub fn run_emulator(
-    cmd_rx: &Receiver<Command>,
-    state_tx: &Sender<State>,
-    cpu: &Arc<Mutex<Processor>>,
-) {
+pub fn run_emulator(cmd_rx: &Receiver<Command>, state_tx: &Sender<State>, cpu: Processor) {
+    println!("starting");
+
     let mut running = Running::Paused;
     let mut addr = 0u32;
     let size = 256;
 
     // Send initial state.
-    let Ok(mut cpu_lock) = cpu.lock() else {
-        panic!("Failed to lock CPU.")
-    };
+    // let Ok(mut cpu_lock) = cpu.lock() else {
+    //     panic!("Failed to lock CPU.")
+    // };
+
+    let mut cpu_lock = cpu;
+
+    cpu_lock.get_stack(32);
+    println!("got stack");
+
+    cpu_lock.display();
+    println!("got display");
 
     let memory_view = cpu_lock.memory.read_range(addr, size);
-    let initial_state = state(cpu, running, 0, memory_view);
+    println!("got view");
+    let initial_state = state(&mut cpu_lock, running, 0, memory_view);
+    println!("got state");
+
     let _ = state_tx.send(initial_state);
+    println!("sent state");
 
     let mut instruction_count = 0;
 
     loop {
+        println!("looping");
+
         let cmd = if running == Running::Running {
             match cmd_rx.try_recv() {
                 Ok(cmd) => Some(cmd),
@@ -50,6 +62,8 @@ pub fn run_emulator(
         };
 
         if let Some(cmd) = cmd {
+            println!("Received command: {:?}", cmd);
+
             match cmd {
                 Command::Start => {
                     running = Running::Running;
@@ -95,7 +109,7 @@ pub fn run_emulator(
             }
 
             let memory_view = cpu_lock.memory.read_range(addr, size);
-            let state = state(cpu, running, instruction_count, memory_view);
+            let state = state(&mut cpu_lock, running, instruction_count, memory_view);
 
             let _ = state_tx.send(state);
         }
@@ -129,7 +143,7 @@ pub fn run_emulator(
 
             if update {
                 let memory_view = cpu_lock.memory.read_range(addr, size);
-                let state = state(cpu, running, instruction_count, memory_view);
+                let state = state(&mut cpu_lock, running, instruction_count, memory_view);
                 let _ = state_tx.send(state);
             }
         } else {
@@ -139,15 +153,11 @@ pub fn run_emulator(
 }
 
 fn state(
-    cpu: &Arc<Mutex<Processor>>,
+    cpu_lock: &mut Processor,
     running: Running,
     instruction_count: usize,
     memory_view: Vec<u8>,
 ) -> State {
-    let Ok(mut cpu_lock) = cpu.lock() else {
-        panic!("Could not lock CPU.")
-    };
-
     State {
         // TODO: Replace with actual register access from your CPU.
         reg_file: cpu_lock.registers,
diff --git a/src/emulator/system/model.rs b/src/emulator/system/model.rs
index 047854b..91e8d65 100644
--- a/src/emulator/system/model.rs
+++ b/src/emulator/system/model.rs
@@ -7,6 +7,14 @@ pub enum Running {
     Halted,
 }
 
+pub trait IODevice: Send + Sync {
+    fn read_byte(&mut self, addr: u32) -> u8;
+    fn write_byte(&mut self, addr: u32, value: u8);
+    fn read_range(&mut self, addr: u32, size: u32) -> Vec<u8>;
+    fn write_range(&mut self, addr: u32, value: Vec<u8>);
+}
+
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub enum Command {
     Start,
     Stop,
diff --git a/src/emulator/system/processor/mod.rs b/src/emulator/system/processor/mod.rs
index bf356d3..cfec952 100644
--- a/src/emulator/system/processor/mod.rs
+++ b/src/emulator/system/processor/mod.rs
@@ -1,27 +1,33 @@
-use std::cmp::{max, min};
+use std::{
+    cmp::{max, min},
+    sync::Arc,
+};
 
 use crate::{
     common::instructions::{Instruction, Interrupt, Register, errors::InstructionDecodeError},
-    emulator::system::{memory::MemoryUnit, model::RegFile},
+    emulator::system::{
+        memory::MemoryUnit,
+        model::{IODevice, RegFile},
+    },
 };
 
 pub struct Processor {
     pub memory: Box<dyn MemoryUnit>,
     pub registers: RegFile,
     pub halted: bool,
-    // pub io_devices: Vec<Arc<dyn IODevice>>,
+    pub io_devices: Vec<Arc<dyn IODevice>>,
 }
 
 #[allow(clippy::needless_pass_by_ref_mut)]
 impl Processor {
-    // io_devices: Vec<Arc<dyn IODevice>>
     #[must_use]
-    pub fn new(memory: Box<dyn MemoryUnit>) -> Self {
+    pub fn new(memory: Box<dyn MemoryUnit>, io_devices: Vec<Arc<dyn IODevice>>) -> Self {
         Self {
             // io_devices,
             memory,
             registers: RegFile::default(),
             halted: false,
+            io_devices,
         }
     }
 
diff --git a/src/emulator/system/processor/tests.rs b/src/emulator/system/processor/tests.rs
index 9a6ce68..fd8d8fa 100644
--- a/src/emulator/system/processor/tests.rs
+++ b/src/emulator/system/processor/tests.rs
@@ -9,7 +9,7 @@ use crate::{
 
 fn create_test_processor() -> Processor {
     let memory = Box::new(MainStore::new());
-    Processor::new(memory)
+    Processor::new(memory, Vec::new())
 }
 
 #[test]
diff --git a/src/main.rs b/src/main.rs
index 0c40f3e..5f3e652 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,14 +17,10 @@ fn main() -> Result<(), eframe::Error> {
     let (state_sender, state_receiver) = std::sync::mpsc::channel();
 
     let mainstore = MainStore::new();
-    let processor = Processor::new(Box::new(mainstore));
+    let processor = Processor::new(Box::new(mainstore), vec![]);
 
     thread::spawn(move || {
-        run_emulator(
-            &cmd_receiver,
-            &state_sender,
-            &Arc::new(Mutex::new(processor)),
-        );
+        run_emulator(&cmd_receiver, &state_sender, processor);
     });
 
     // Create UI