diff --git a/src/apu/mod.rs b/src/apu/mod.rs
index 7e48c5f..b4cee46 100644
--- a/src/apu/mod.rs
+++ b/src/apu/mod.rs
@@ -1,436 +1,438 @@
-//! APU Component
-
-use crate::bus::interrupt::Interrupt;
-use std::cell::RefCell;
-use std::rc::Rc;
-use sdl2::mixer::{InitFlag, AUDIO_U8};
-
-pub struct Apu {
-    sdl_audio: sdl2::AudioSubsystem,
-    interrupt_bus: Rc<RefCell<Interrupt>>,
-    pulse_1: Pulse,
-    pulse_2: Pulse,
-    noise: Noise,
-    triangle: Triangle,
-    dmc: Dmc,
-
-    enable_dmc: bool,
-    enable_noise: bool,
-    enable_triangle: bool,
-    enable_pulse_1: bool,
-    enable_pulse_2: bool,
-
-    // Temporary debug variables
-    phase_inc: f32,
-    phase: f32,
-    volume: f32
-}
-
-impl Apu {
-    /// Instantiate APU component
-    pub fn new(_interrupt_bus: Rc<RefCell<Interrupt>>, _sdl_context: Rc<RefCell<sdl2::Sdl>>) -> Apu {
-        let mut apu = Apu {
-            sdl_audio: _sdl_context.borrow_mut().audio().unwrap(),
-            interrupt_bus: _interrupt_bus,
-            pulse_1: Pulse{
-                byte_0: 0,
-                byte_1: 0,
-                byte_2: 0,
-                byte_3: 0,
-                duty: 0,
-                enveloppe_loop_length_counter_halt: false,
-                constant_volume: false,
-                volume_envelope: 0,
-                sweep_unit_enabled: false,
-                sweep_unit_period: 0,
-                sweep_unit_negate: false,
-                sweep_unit_shift: 0,
-                timer: 0,
-                length_counter_load: 0,
-            },
-            pulse_2: Pulse{
-                byte_0: 0,
-                byte_1: 0,
-                byte_2: 0,
-                byte_3: 0,
-                duty: 0,
-                enveloppe_loop_length_counter_halt: false,
-                constant_volume: false,
-                volume_envelope: 0,
-                sweep_unit_enabled: false,
-                sweep_unit_period: 0,
-                sweep_unit_negate: false,
-                sweep_unit_shift: 0,
-                timer: 0,
-                length_counter_load: 0,
-            },
-            triangle: Triangle {
-                byte_0: 0,
-                byte_2: 0,
-                byte_3: 0,
-                lenght_counter_halt_linear_counter_control: false,
-                linear_counter_load: 0,
-                length_counter_load: 0,
-                timer: 0,
-            },
-            noise: Noise {
-                byte_0: 0,
-                byte_2: 0,
-                byte_3: 0,
-                envelope_loop_length_counter_halt: false,
-                constant_volume: false,
-                volume_envelope: 0,
-                loop_noise: false,
-                noise_period: 0,
-                length_counter_load: 0,
-            },
-            dmc: Dmc {
-                byte_0: 0,
-                irq_enabled: false,
-                loop_sample: false,
-                frequency: 0,
-                load_counter: 0,
-                sample_address: 0,
-                sample_length: 0,
-            },
-
-            enable_dmc: false,
-            enable_noise: false,
-            enable_triangle: false,
-            enable_pulse_1: false,
-            enable_pulse_2: false,
-
-            // Temporary debug variables
-            phase_inc: 440.0 / spec.freq as f32,
-            phase: 0.0,
-            volume: 0.25
-        };
-
-        // Initialise registers
-        apu.pulse_1.set_byte_0(0x30);
-        apu.pulse_1.set_byte_1(0x08);
-        apu.pulse_1.set_byte_2(0x00);
-        apu.pulse_1.set_byte_3(0x00);
-        apu.pulse_2.set_byte_0(0x30);
-        apu.pulse_2.set_byte_1(0x08);
-        apu.pulse_2.set_byte_2(0x00);
-        apu.pulse_2.set_byte_3(0x00);
-        apu.triangle.set_byte_0(0x80);
-        apu.triangle.set_byte_2(0x00);
-        apu.triangle.set_byte_3(0x00);
-        apu.noise.set_byte_0(0x30);
-        apu.noise.set_byte_2(0x00);
-        apu.noise.set_byte_3(0x00);
-        apu.dmc.set_byte_0(0x00);
-        apu.dmc.set_byte_1(0x00);
-        apu.dmc.set_byte_2(0x00);
-        apu.dmc.set_byte_3(0x00);
-
-        apu
-    }
-
-    pub fn start(&mut self) {
-        let desired_spec = AudioSpecDesired {
-            freq: Some(44100),
-            channels: Some(1),  // mono
-            samples: None       // default sample size
-        };
-
-        let device = audio_subsystem.open_playback(None, &desired_spec, |spec| {
-            self // Use APU as AudioCallback if allowed
-        }).unwrap();
-
-        // Start playing sound
-        device.resume();
-    }
-
-    /// Next APU cycle
-    pub fn next(&self) {
-    }
-
-    /// Read APU registers
-    pub fn read_registers(&mut self, address: u16) -> u8 {
-        match address {
-            0x4000 => self.pulse_1.get_byte_0(),
-            0x4001 => self.pulse_1.get_byte_1(),
-            0x4002 => self.pulse_1.get_byte_2(),
-            0x4003 => self.pulse_1.get_byte_3(),
-            0x4004 => self.pulse_2.get_byte_0(),
-            0x4005 => self.pulse_2.get_byte_1(),
-            0x4006 => self.pulse_2.get_byte_2(),
-            0x4007 => self.pulse_2.get_byte_3(),
-            0x4008 => self.triangle.get_byte_0(),
-            0x4009 => 0, // Unused
-            0x400a => self.triangle.get_byte_2(),
-            0x400b => self.triangle.get_byte_3(),
-            0x400c => self.noise.get_byte_0(),
-            0x400d => 0, // Unused
-            0x400e => self.noise.get_byte_2(),
-            0x400f => self.noise.get_byte_3(),
-            0x4010 => self.dmc.get_byte_0(),
-            0x4011 => self.dmc.get_byte_1(),
-            0x4012 => self.dmc.get_byte_2(),
-            0x4013 => self.dmc.get_byte_3(),
-            0x4015 => self.get_status(),
-            0x4017 => self.get_frame_counter(),
-            _ => 0,
-        }
-    }
-
-    /// Write APU registers
-    pub fn write_registers(&mut self, address: u16, value: u8) {
-        match address {
-            0x4000 => self.pulse_1.set_byte_0(value),
-            0x4001 => self.pulse_1.set_byte_1(value),
-            0x4002 => self.pulse_1.set_byte_2(value),
-            0x4003 => self.pulse_1.set_byte_3(value),
-            0x4004 => self.pulse_2.set_byte_0(value),
-            0x4005 => self.pulse_2.set_byte_1(value),
-            0x4006 => self.pulse_2.set_byte_2(value),
-            0x4007 => self.pulse_2.set_byte_3(value),
-            0x4008 => self.triangle.set_byte_0(value),
-            0x4009 => (), // Unused
-            0x400a => self.triangle.set_byte_2(value),
-            0x400b => self.triangle.set_byte_3(value),
-            0x400c => self.noise.set_byte_0(value),
-            0x400d => (), // Unused
-            0x400e => self.noise.set_byte_2(value),
-            0x400f => self.noise.set_byte_3(value),
-            0x4010 => self.dmc.set_byte_0(value),
-            0x4011 => self.dmc.set_byte_1(value),
-            0x4012 => self.dmc.set_byte_2(value),
-            0x4013 => self.dmc.set_byte_3(value),
-            0x4015 => self.set_status(value),
-            0x4017 => self.set_frame_counter(value),
-            _ => (),
-        };
-    }
-
-    fn get_status(&self) -> u8 {
-        0
-    }
-
-    fn set_status(&mut self, value: u8) {
-
-    }
-
-    fn get_frame_counter(&self) -> u8 {
-        0
-    }
-
-    fn set_frame_counter(&mut self, value: u8) {
-
-    }
-}
-
-impl AudioCallback for Apu {
-    // Temporary approach. Will need to be changed to represent NES APU function
-    type Channel = f32;
-    fn callback(&mut self, out: &mut[f32]) {
-        for x in out.iter_mut() {
-            *x = match self.phase {
-                0.0...0.5 => self.volume,
-                _ => -self.volume
-            };
-            self.phase = (self.phase + self.phase_inc) % 1.0;
-        }
-    }
-}
-
-/// Pulse register
-struct Pulse {
-    byte_0: u8,
-    byte_1: u8,
-    byte_2: u8,
-    byte_3: u8,
-    duty: u8,
-    enveloppe_loop_length_counter_halt: bool,
-    constant_volume: bool,
-    volume_envelope: u8,
-    sweep_unit_enabled: bool,
-    sweep_unit_period: u8,
-    sweep_unit_negate: bool,
-    sweep_unit_shift: u8,
-    timer: u16,
-    length_counter_load: u8,
-}
-
-impl Pulse {
-    pub fn set_byte_0(&mut self, value: u8) {
-        self.byte_0 = value;
-        self.duty = value >> 6;
-        self.enveloppe_loop_length_counter_halt = (value & 0b100000) != 0;
-        self.constant_volume = (value & 0b10000) != 0;
-        self.volume_envelope = value & 0b1111
-    }
-
-    pub fn get_byte_0(&self) -> u8 {
-        self.byte_0
-    }
-
-    pub fn set_byte_1(&mut self, value: u8) {
-        self.byte_1 = value;
-        self.sweep_unit_enabled = (value & 0b10000000) != 0;
-        self.sweep_unit_period = (value >> 4) & 0b111;
-        self.sweep_unit_negate = (value & 0b1000) != 0;
-        self.sweep_unit_shift = value & 0b111;
-    }
-
-    pub fn get_byte_1(&self) -> u8 {
-        self.byte_1
-    }
-
-    pub fn set_byte_2(&mut self, value: u8) {
-        self.byte_2 = value;
-        self.timer = (self.timer & 0xff00) | (value as u16);
-    }
-
-    pub fn get_byte_2(&self) -> u8 {
-        self.byte_2
-    }
-
-    pub fn set_byte_3(&mut self, value: u8) {
-        self.byte_3 = value;
-        self.length_counter_load = value >> 3;
-        self.timer = (self.timer & 0xff) | ((value as u16 & 0b111) << 8);
-    }
-
-    pub fn get_byte_3(&self) -> u8 {
-        self.byte_3
-    }
-}
-
-/// Triangle register
-struct Triangle {
-    byte_0: u8,
-    byte_2: u8,
-    byte_3: u8,
-    lenght_counter_halt_linear_counter_control: bool,
-    linear_counter_load: u8,
-    length_counter_load: u8,
-    timer: u16,
-}
-
-impl Triangle {
-    pub fn set_byte_0(&mut self, value: u8) {
-        self.byte_0 = value;
-        self.lenght_counter_halt_linear_counter_control = (value & 0b10000000) != 0;
-        self.linear_counter_load = value & 0x7f;
-    }
-
-    pub fn get_byte_0(&self) -> u8 {
-        self.byte_0
-    }
-
-    pub fn set_byte_2(&mut self, value: u8) {
-        self.byte_2 = value;
-        self.timer = (self.timer & 0xff00) | (value as u16);
-    }
-
-    pub fn get_byte_2(&self) -> u8 {
-        self.byte_2
-    }
-
-    pub fn set_byte_3(&mut self, value: u8) {
-        self.byte_3 = value;
-        self.length_counter_load = value >> 3;
-        self.timer = (self.timer & 0xff) | ((value as u16 & 0b111) << 8);
-    }
-
-    pub fn get_byte_3(&self) -> u8 {
-        self.byte_3
-    }
-}
-
-/// Noise register
-struct Noise {
-    byte_0: u8,
-    byte_2: u8,
-    byte_3: u8,
-    envelope_loop_length_counter_halt: bool,
-    constant_volume: bool,
-    volume_envelope: u8,
-    loop_noise: bool,
-    noise_period: u8,
-    length_counter_load: u8,
-}
-
-impl Noise {
-    pub fn set_byte_0(&mut self, value: u8) {
-        self.byte_0 = value;
-        self.envelope_loop_length_counter_halt = (value & 0b100000) != 0;
-        self.constant_volume = (value & 0b10000) != 0;
-        self.volume_envelope = value & 0b1111;
-    }
-
-    pub fn get_byte_0(&self) -> u8 {
-        self.byte_0
-    }
-
-    pub fn set_byte_2(&mut self, value: u8) {
-        self.byte_2 = value;
-        self.loop_noise = (value & 0x80) != 0;
-        self.noise_period = value & 0xf;
-    }
-
-    pub fn get_byte_2(&self) -> u8 {
-        self.byte_2
-    }
-
-    pub fn set_byte_3(&mut self, value: u8) {
-        self.byte_3 = value;
-        self.length_counter_load = value >> 3;
-    }
-
-    pub fn get_byte_3(&self) -> u8 {
-        self.byte_3
-    }
-}
-
-/// DMC Register
-struct Dmc {
-    byte_0: u8,
-    irq_enabled: bool,
-    loop_sample: bool,
-    frequency: u8,
-    load_counter: u8,
-    sample_address: u8,
-    sample_length: u8,
-}
-
-impl Dmc {
-    pub fn set_byte_0(&mut self, value: u8) {
-        self.byte_0 = value;
-        self.irq_enabled = (value & 0x80) != 0;
-        self.loop_sample = (value & 0x40) != 0;
-        self.frequency = value & 0xf;
-    }
-
-    pub fn get_byte_0(&self) -> u8 {
-        self.byte_0
-    }
-
-    pub fn set_byte_1(&mut self, value: u8) {
-        self.load_counter = value & 0x7f;
-    }
-
-    pub fn get_byte_1(&self) -> u8 {
-        self.load_counter
-    }
-
-    pub fn set_byte_2(&mut self, value: u8) {
-        self.sample_address = value;
-    }
-
-    pub fn get_byte_2(&self) -> u8 {
-        self.sample_address
-    }
-
-    pub fn set_byte_3(&mut self, value: u8) {
-        self.sample_length = value;
-    }
-
-    pub fn get_byte_3(&self) -> u8 {
-        self.sample_length
-    }
-}
+//! APU Component
+
+use crate::bus::interrupt::Interrupt;
+use std::cell::RefCell;
+use std::rc::Rc;
+use sdl2::mixer::{InitFlag, AUDIO_U8};
+
+/// Apu is the main struct for the APU component.
+/// It is triggerd by NES Emulator main thread
+pub struct Apu {
+    sdl_audio: sdl2::AudioSubsystem,
+    interrupt_bus: Rc<RefCell<Interrupt>>,
+    pulse_1: Pulse,
+    pulse_2: Pulse,
+    noise: Noise,
+    triangle: Triangle,
+    dmc: Dmc,
+
+    enable_dmc: bool,
+    enable_noise: bool,
+    enable_triangle: bool,
+    enable_pulse_1: bool,
+    enable_pulse_2: bool,
+
+    // Temporary debug variables
+    phase_inc: f32,
+    phase: f32,
+    volume: f32
+}
+
+impl Apu {
+    /// Instantiate APU component
+    pub fn new(_interrupt_bus: Rc<RefCell<Interrupt>>, _sdl_context: Rc<RefCell<sdl2::Sdl>>) -> Apu {
+        let mut apu = Apu {
+            sdl_audio: _sdl_context.borrow_mut().audio().unwrap(),
+            interrupt_bus: _interrupt_bus,
+            pulse_1: Pulse{
+                byte_0: 0,
+                byte_1: 0,
+                byte_2: 0,
+                byte_3: 0,
+                duty: 0,
+                enveloppe_loop_length_counter_halt: false,
+                constant_volume: false,
+                volume_envelope: 0,
+                sweep_unit_enabled: false,
+                sweep_unit_period: 0,
+                sweep_unit_negate: false,
+                sweep_unit_shift: 0,
+                timer: 0,
+                length_counter_load: 0,
+            },
+            pulse_2: Pulse{
+                byte_0: 0,
+                byte_1: 0,
+                byte_2: 0,
+                byte_3: 0,
+                duty: 0,
+                enveloppe_loop_length_counter_halt: false,
+                constant_volume: false,
+                volume_envelope: 0,
+                sweep_unit_enabled: false,
+                sweep_unit_period: 0,
+                sweep_unit_negate: false,
+                sweep_unit_shift: 0,
+                timer: 0,
+                length_counter_load: 0,
+            },
+            triangle: Triangle {
+                byte_0: 0,
+                byte_2: 0,
+                byte_3: 0,
+                lenght_counter_halt_linear_counter_control: false,
+                linear_counter_load: 0,
+                length_counter_load: 0,
+                timer: 0,
+            },
+            noise: Noise {
+                byte_0: 0,
+                byte_2: 0,
+                byte_3: 0,
+                envelope_loop_length_counter_halt: false,
+                constant_volume: false,
+                volume_envelope: 0,
+                loop_noise: false,
+                noise_period: 0,
+                length_counter_load: 0,
+            },
+            dmc: Dmc {
+                byte_0: 0,
+                irq_enabled: false,
+                loop_sample: false,
+                frequency: 0,
+                load_counter: 0,
+                sample_address: 0,
+                sample_length: 0,
+            },
+
+            enable_dmc: false,
+            enable_noise: false,
+            enable_triangle: false,
+            enable_pulse_1: false,
+            enable_pulse_2: false,
+
+            // Temporary debug variables
+            phase_inc: 440.0 / spec.freq as f32,
+            phase: 0.0,
+            volume: 0.25
+        };
+
+        // Initialise registers
+        apu.pulse_1.set_byte_0(0x30);
+        apu.pulse_1.set_byte_1(0x08);
+        apu.pulse_1.set_byte_2(0x00);
+        apu.pulse_1.set_byte_3(0x00);
+        apu.pulse_2.set_byte_0(0x30);
+        apu.pulse_2.set_byte_1(0x08);
+        apu.pulse_2.set_byte_2(0x00);
+        apu.pulse_2.set_byte_3(0x00);
+        apu.triangle.set_byte_0(0x80);
+        apu.triangle.set_byte_2(0x00);
+        apu.triangle.set_byte_3(0x00);
+        apu.noise.set_byte_0(0x30);
+        apu.noise.set_byte_2(0x00);
+        apu.noise.set_byte_3(0x00);
+        apu.dmc.set_byte_0(0x00);
+        apu.dmc.set_byte_1(0x00);
+        apu.dmc.set_byte_2(0x00);
+        apu.dmc.set_byte_3(0x00);
+
+        apu
+    }
+
+    pub fn start(&mut self) {
+        let desired_spec = AudioSpecDesired {
+            freq: Some(44100),
+            channels: Some(1),  // mono
+            samples: None       // default sample size
+        };
+
+        let device = audio_subsystem.open_playback(None, &desired_spec, |spec| {
+            self // Use APU as AudioCallback if allowed
+        }).unwrap();
+
+        // Start playing sound
+        device.resume();
+    }
+
+    /// Next APU cycle
+    pub fn next(&self) {
+    }
+
+    /// Read APU registers
+    pub fn read_registers(&mut self, address: u16) -> u8 {
+        match address {
+            0x4000 => self.pulse_1.get_byte_0(),
+            0x4001 => self.pulse_1.get_byte_1(),
+            0x4002 => self.pulse_1.get_byte_2(),
+            0x4003 => self.pulse_1.get_byte_3(),
+            0x4004 => self.pulse_2.get_byte_0(),
+            0x4005 => self.pulse_2.get_byte_1(),
+            0x4006 => self.pulse_2.get_byte_2(),
+            0x4007 => self.pulse_2.get_byte_3(),
+            0x4008 => self.triangle.get_byte_0(),
+            0x4009 => 0, // Unused
+            0x400a => self.triangle.get_byte_2(),
+            0x400b => self.triangle.get_byte_3(),
+            0x400c => self.noise.get_byte_0(),
+            0x400d => 0, // Unused
+            0x400e => self.noise.get_byte_2(),
+            0x400f => self.noise.get_byte_3(),
+            0x4010 => self.dmc.get_byte_0(),
+            0x4011 => self.dmc.get_byte_1(),
+            0x4012 => self.dmc.get_byte_2(),
+            0x4013 => self.dmc.get_byte_3(),
+            0x4015 => self.get_status(),
+            0x4017 => self.get_frame_counter(),
+            _ => 0,
+        }
+    }
+
+    /// Write APU registers
+    pub fn write_registers(&mut self, address: u16, value: u8) {
+        match address {
+            0x4000 => self.pulse_1.set_byte_0(value),
+            0x4001 => self.pulse_1.set_byte_1(value),
+            0x4002 => self.pulse_1.set_byte_2(value),
+            0x4003 => self.pulse_1.set_byte_3(value),
+            0x4004 => self.pulse_2.set_byte_0(value),
+            0x4005 => self.pulse_2.set_byte_1(value),
+            0x4006 => self.pulse_2.set_byte_2(value),
+            0x4007 => self.pulse_2.set_byte_3(value),
+            0x4008 => self.triangle.set_byte_0(value),
+            0x4009 => (), // Unused
+            0x400a => self.triangle.set_byte_2(value),
+            0x400b => self.triangle.set_byte_3(value),
+            0x400c => self.noise.set_byte_0(value),
+            0x400d => (), // Unused
+            0x400e => self.noise.set_byte_2(value),
+            0x400f => self.noise.set_byte_3(value),
+            0x4010 => self.dmc.set_byte_0(value),
+            0x4011 => self.dmc.set_byte_1(value),
+            0x4012 => self.dmc.set_byte_2(value),
+            0x4013 => self.dmc.set_byte_3(value),
+            0x4015 => self.set_status(value),
+            0x4017 => self.set_frame_counter(value),
+            _ => (),
+        };
+    }
+
+    fn get_status(&self) -> u8 {
+        0
+    }
+
+    fn set_status(&mut self, value: u8) {
+
+    }
+
+    fn get_frame_counter(&self) -> u8 {
+        0
+    }
+
+    fn set_frame_counter(&mut self, value: u8) {
+
+    }
+}
+
+impl AudioCallback for Apu {
+    // Temporary approach. Will need to be changed to represent NES APU function
+    type Channel = f32;
+    fn callback(&mut self, out: &mut[f32]) {
+        for x in out.iter_mut() {
+            *x = match self.phase {
+                0.0...0.5 => self.volume,
+                _ => -self.volume
+            };
+            self.phase = (self.phase + self.phase_inc) % 1.0;
+        }
+    }
+}
+
+/// Pulse register
+struct Pulse {
+    byte_0: u8,
+    byte_1: u8,
+    byte_2: u8,
+    byte_3: u8,
+    duty: u8,
+    enveloppe_loop_length_counter_halt: bool,
+    constant_volume: bool,
+    volume_envelope: u8,
+    sweep_unit_enabled: bool,
+    sweep_unit_period: u8,
+    sweep_unit_negate: bool,
+    sweep_unit_shift: u8,
+    timer: u16,
+    length_counter_load: u8,
+}
+
+impl Pulse {
+    pub fn set_byte_0(&mut self, value: u8) {
+        self.byte_0 = value;
+        self.duty = value >> 6;
+        self.enveloppe_loop_length_counter_halt = (value & 0b100000) != 0;
+        self.constant_volume = (value & 0b10000) != 0;
+        self.volume_envelope = value & 0b1111
+    }
+
+    pub fn get_byte_0(&self) -> u8 {
+        self.byte_0
+    }
+
+    pub fn set_byte_1(&mut self, value: u8) {
+        self.byte_1 = value;
+        self.sweep_unit_enabled = (value & 0b10000000) != 0;
+        self.sweep_unit_period = (value >> 4) & 0b111;
+        self.sweep_unit_negate = (value & 0b1000) != 0;
+        self.sweep_unit_shift = value & 0b111;
+    }
+
+    pub fn get_byte_1(&self) -> u8 {
+        self.byte_1
+    }
+
+    pub fn set_byte_2(&mut self, value: u8) {
+        self.byte_2 = value;
+        self.timer = (self.timer & 0xff00) | (value as u16);
+    }
+
+    pub fn get_byte_2(&self) -> u8 {
+        self.byte_2
+    }
+
+    pub fn set_byte_3(&mut self, value: u8) {
+        self.byte_3 = value;
+        self.length_counter_load = value >> 3;
+        self.timer = (self.timer & 0xff) | ((value as u16 & 0b111) << 8);
+    }
+
+    pub fn get_byte_3(&self) -> u8 {
+        self.byte_3
+    }
+}
+
+/// Triangle register
+struct Triangle {
+    byte_0: u8,
+    byte_2: u8,
+    byte_3: u8,
+    lenght_counter_halt_linear_counter_control: bool,
+    linear_counter_load: u8,
+    length_counter_load: u8,
+    timer: u16,
+}
+
+impl Triangle {
+    pub fn set_byte_0(&mut self, value: u8) {
+        self.byte_0 = value;
+        self.lenght_counter_halt_linear_counter_control = (value & 0b10000000) != 0;
+        self.linear_counter_load = value & 0x7f;
+    }
+
+    pub fn get_byte_0(&self) -> u8 {
+        self.byte_0
+    }
+
+    pub fn set_byte_2(&mut self, value: u8) {
+        self.byte_2 = value;
+        self.timer = (self.timer & 0xff00) | (value as u16);
+    }
+
+    pub fn get_byte_2(&self) -> u8 {
+        self.byte_2
+    }
+
+    pub fn set_byte_3(&mut self, value: u8) {
+        self.byte_3 = value;
+        self.length_counter_load = value >> 3;
+        self.timer = (self.timer & 0xff) | ((value as u16 & 0b111) << 8);
+    }
+
+    pub fn get_byte_3(&self) -> u8 {
+        self.byte_3
+    }
+}
+
+/// Noise register
+struct Noise {
+    byte_0: u8,
+    byte_2: u8,
+    byte_3: u8,
+    envelope_loop_length_counter_halt: bool,
+    constant_volume: bool,
+    volume_envelope: u8,
+    loop_noise: bool,
+    noise_period: u8,
+    length_counter_load: u8,
+}
+
+impl Noise {
+    pub fn set_byte_0(&mut self, value: u8) {
+        self.byte_0 = value;
+        self.envelope_loop_length_counter_halt = (value & 0b100000) != 0;
+        self.constant_volume = (value & 0b10000) != 0;
+        self.volume_envelope = value & 0b1111;
+    }
+
+    pub fn get_byte_0(&self) -> u8 {
+        self.byte_0
+    }
+
+    pub fn set_byte_2(&mut self, value: u8) {
+        self.byte_2 = value;
+        self.loop_noise = (value & 0x80) != 0;
+        self.noise_period = value & 0xf;
+    }
+
+    pub fn get_byte_2(&self) -> u8 {
+        self.byte_2
+    }
+
+    pub fn set_byte_3(&mut self, value: u8) {
+        self.byte_3 = value;
+        self.length_counter_load = value >> 3;
+    }
+
+    pub fn get_byte_3(&self) -> u8 {
+        self.byte_3
+    }
+}
+
+/// DMC Register
+struct Dmc {
+    byte_0: u8,
+    irq_enabled: bool,
+    loop_sample: bool,
+    frequency: u8,
+    load_counter: u8,
+    sample_address: u8,
+    sample_length: u8,
+}
+
+impl Dmc {
+    pub fn set_byte_0(&mut self, value: u8) {
+        self.byte_0 = value;
+        self.irq_enabled = (value & 0x80) != 0;
+        self.loop_sample = (value & 0x40) != 0;
+        self.frequency = value & 0xf;
+    }
+
+    pub fn get_byte_0(&self) -> u8 {
+        self.byte_0
+    }
+
+    pub fn set_byte_1(&mut self, value: u8) {
+        self.load_counter = value & 0x7f;
+    }
+
+    pub fn get_byte_1(&self) -> u8 {
+        self.load_counter
+    }
+
+    pub fn set_byte_2(&mut self, value: u8) {
+        self.sample_address = value;
+    }
+
+    pub fn get_byte_2(&self) -> u8 {
+        self.sample_address
+    }
+
+    pub fn set_byte_3(&mut self, value: u8) {
+        self.sample_length = value;
+    }
+
+    pub fn get_byte_3(&self) -> u8 {
+        self.sample_length
+    }
+}