diff --git a/src/emu/cpu.rs b/src/emu/cpu.rs
index 65274d1..8357c05 100644
--- a/src/emu/cpu.rs
+++ b/src/emu/cpu.rs
@@ -1,4 +1,8 @@
 use crate::emu::mmu::{MappedMemory, Memory};
+use crate::emu::program_counter::ProgramCounter;
+use crate::misc::emulator_error::{DeviceType, EmulatorError};
+use crate::misc::emulator_error::DeviceType::{CPU, PC};
+use crate::misc::endian::read_big_endian_u24;
 use crate::misc::result::EmulatorResult;
 
 #[derive(Debug)]
@@ -9,24 +13,49 @@ pub enum CpuState{
 
 #[derive(Debug)]
 pub struct Cpu<'a>{
-    mapped_memory:&'a mut MappedMemory<'a>,
+    mapped_memory:&'a MappedMemory<'a>,
+    program_counter: &'a ProgramCounter
 }
 
 impl <'a> Cpu<'a>{
-    pub fn new(mapped_memory: &'a mut MappedMemory<'a>)->Cpu<'a>{
+    pub fn new(mapped_memory: &'a MappedMemory<'a>,program_counter: &'a ProgramCounter)->Cpu<'a>{
         Cpu{
-            mapped_memory
+            mapped_memory,
+            program_counter
         }
     }
-    pub fn cycle()->EmulatorResult<()>{
-        todo!();
+    pub fn cycle(&self)->EmulatorResult<()>{
+        for _i in 0..65536{
+            let address_to_execute = self.program_counter.get_pc_value();
+
+            //fetch
+            let num1 = self.fetch_triplet(address_to_execute)?;
+            self.set_triplet(address_to_execute+3,&num1)?;
+
+            let new_pc = read_big_endian_u24(&self.fetch_triplet(address_to_execute+6)?);
+            self.program_counter.set_address(new_pc)?;
+        }
+        // TODO send graphics
+        // TODO send audio
+        Ok(())
+    }
+
+    fn fetch_triplet(&self, address: u32) -> EmulatorResult<[u8;3]> {
+        let first_byte = self.mapped_memory.try_get_byte(address)?;
+        let second_byte = self.mapped_memory.try_get_byte(address+1)?;
+        let third_byte = self.mapped_memory.try_get_byte(address+2)?;
+        let num = [first_byte,second_byte,third_byte];
+        Ok(num)
+    }
+    fn set_triplet(&self, address: u32, val:&[u8;3]) -> EmulatorResult<()> {
+        self.mapped_memory.try_set_byte(address, val[0])?;
+        self.mapped_memory.try_set_byte(address + 1, val[1])?;
+        self.mapped_memory.try_set_byte(address + 2, val[2])?;
         Ok(())
     }
     fn set_pc(&self,value: &[u8;3])->EmulatorResult<()>{
-            todo!()
-        // for bytete in value {
-        //     self.mapped_memory.try_set_byte()
-        // }try_set_byte
+        let x = read_big_endian_u24(value);
+        self.program_counter.set_address(x)
     }
 }
 
diff --git a/src/main.rs b/src/main.rs
index 8047a34..c5e2021 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@ use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 use sdl2::pixels::Color;
 use simple_logger::SimpleLogger;
+use crate::emu::cpu::Cpu;
 use crate::emu::iomem::MemoryMappedIO;
 use crate::emu::ram::RamMemory;
 use crate::emu::mmu::{Memory, MappedMemory};
@@ -22,6 +23,10 @@ fn main() -> EmulatorResult<()> {
     let ram = RamMemory::try_new()?;
     let mmu = MappedMemory::new(&mmio,&ram);
 
+    let mut cpu = Cpu::new(&mmu,&program_counter);
+    for i in 0..1{
+        cpu.cycle();
+    }
 
     // let sdl_context = sdl2::init().unwrap();
     // let video_subsystem = sdl_context.video().unwrap();
diff --git a/src/misc/emulator_error.rs b/src/misc/emulator_error.rs
index 4a010c3..21e2336 100644
--- a/src/misc/emulator_error.rs
+++ b/src/misc/emulator_error.rs
@@ -2,6 +2,7 @@ use std::fmt::Debug;
 
 #[derive(Debug, Copy, Clone)]
 pub enum DeviceType {
+    CPU,
     RAM,
     MMU,
     /// Program counter