diff --git a/src/emu/cpu.rs b/src/emu/cpu.rs
index e0b002e..b4e2490 100644
--- a/src/emu/cpu.rs
+++ b/src/emu/cpu.rs
@@ -1,6 +1,5 @@
 use crate::emu::graphics::GraphicsProcessor;
-use crate::emu::mmu::{ Memory};
-use crate::emu::ram::RamMemory;
+use crate::emu::memory::{Memory, RamMemory};
 use crate::misc::endian::{read_big_endian_u24, write_big_endian_u24};
 use crate::misc::result::EmulatorResult;
 
diff --git a/src/emu/graphics.rs b/src/emu/graphics.rs
index 7090532..a63cf2b 100644
--- a/src/emu/graphics.rs
+++ b/src/emu/graphics.rs
@@ -1,6 +1,6 @@
 use std::cell::{Ref, RefCell};
-use crate::emu::mmu::Memory;
-use crate::emu::ram::RamMemory;
+use crate::emu::memory::Memory;
+use crate::emu::memory::RamMemory;
 use crate::misc::emulator_error::DeviceType::GRAPHICS;
 use crate::misc::emulator_error::EmulatorError;
 use crate::misc::result::EmulatorResult;
diff --git a/src/emu/ram.rs b/src/emu/memory.rs
similarity index 89%
rename from src/emu/ram.rs
rename to src/emu/memory.rs
index 9d8edee..a289828 100644
--- a/src/emu/ram.rs
+++ b/src/emu/memory.rs
@@ -1,14 +1,20 @@
 use std::cell::RefCell;
 
-use crate::emu::mmu::Memory;
 use crate::misc::emulator_error::DeviceType::RAM;
 use crate::misc::emulator_error::EmulatorError;
 use crate::misc::endian::read_big_endian_u24;
 use crate::misc::result::EmulatorResult;
 
-const MAPPED_MEMORY_NOT_REQUIRED: u8 = 8;
-
 pub const MEM_LENGTH: usize = 2 << 23;
+
+/// mapped I/O + RAM.
+pub trait Memory {
+    /// Get the value (24bit) at the address(24bit)
+    fn try_get_byte(&self, address: u32) -> EmulatorResult<u8>;
+    /// Set the value at the 24bit address
+    fn try_set_byte(&self, address: u32, value: u8) -> EmulatorResult<()>;
+}
+
 #[derive(Clone, Debug)]
 pub struct RamMemory {
     pub data: RefCell<Box<[u8; MEM_LENGTH]>>,
@@ -54,8 +60,6 @@ impl RamMemory {
 
 
 }
-
-
 impl Memory for RamMemory {
     fn try_get_byte(&self, address: u32) -> EmulatorResult<u8> {
         log::trace!("Fetch RAM memory at address {}",address);
@@ -79,8 +83,8 @@ impl Memory for RamMemory {
 
 #[cfg(test)]
 mod tests{
-    use crate::emu::ram::RamMemory;
-    use crate::emu::mmu::Memory;
+    use crate::emu::memory::RamMemory;
+    use crate::emu::memory::Memory;
     const EXAMPLE_ADDRESS:u32=0x24;
 
     #[test]
@@ -98,4 +102,6 @@ mod tests{
         assert_eq!(0,byte_before);
         assert_eq!(EXAMPLE_DATA,byte_after);
     }
-}
\ No newline at end of file
+}
+
+
diff --git a/src/emu/mmu.rs b/src/emu/mmu.rs
deleted file mode 100644
index 8a71bd5..0000000
--- a/src/emu/mmu.rs
+++ /dev/null
@@ -1,11 +0,0 @@
-use crate::misc::result::EmulatorResult;
-
-/// mapped I/O + RAM.
-pub trait Memory {
-    /// Get the value (24bit) at the address(24bit)
-    fn try_get_byte(&self, address: u32) -> EmulatorResult<u8>;
-    /// Set the value at the 24bit address
-    fn try_set_byte(&self, address: u32, value: u8) -> EmulatorResult<()>;
-}
-
-
diff --git a/src/emu/mod.rs b/src/emu/mod.rs
index be48bdd..b40a4fb 100644
--- a/src/emu/mod.rs
+++ b/src/emu/mod.rs
@@ -1,4 +1,3 @@
 pub mod cpu;
-pub mod mmu;
-pub mod ram;
+pub mod memory;
 pub mod graphics;
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index 16ec88a..f19bd7b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,7 +9,7 @@ use sdl2::render::WindowCanvas;
 use simple_logger::SimpleLogger;
 use crate::emu::cpu::Cpu;
 use crate::emu::graphics::GraphicsProcessor;
-use crate::emu::ram::{MEM_LENGTH, RamMemory};
+use crate::emu::memory::{MEM_LENGTH, RamMemory};
 use crate::graphics::graphics_adapter::SDLGraphicsAdapter;
 
 use crate::misc::result::EmulatorResult;
diff --git a/src/misc/emulator_error.rs b/src/misc/emulator_error.rs
index d1270d9..8317fc9 100644
--- a/src/misc/emulator_error.rs
+++ b/src/misc/emulator_error.rs
@@ -7,9 +7,6 @@ use crate::misc::emulator_error::EmulatorError::EmulatorIOError;
 pub enum DeviceType {
     CPU,
     RAM,
-    MMU,
-    /// Program counter
-    PC,
     KEYBOARD,
     AUDIO,
     GRAPHICS,