diff --git a/gb/bus.go b/gb/bus.go
new file mode 100644
index 0000000..c6ebd2e
--- /dev/null
+++ b/gb/bus.go
@@ -0,0 +1,35 @@
+package gb
+
+// import (
+// 	"fmt"
+// )
+
+// type Bus struct {
+// 	Cart *Cartridge
+// }
+
+// func NewBus(cart *Cartridge) *Bus {
+// 	bus := Bus{Cart: cart}
+
+// 	return &bus
+// }
+
+// func (bus *Bus) Read(address uint16) (byte, error) {
+// 	if address < 0x8000 {
+// 		// ROM data
+// 		return bus.Cart.Read(address), nil
+// 	} else {
+// 		return 0, fmt.Errorf("Reading from address %X not implemented!", address)
+// 	}
+// }
+
+// func (bus *Bus) Write(address uint16, value byte) error {
+// 	if address < 0x8000 {
+// 		// ROM data
+// 		bus.Cart.Write(address, value)
+
+// 		return nil
+// 	} else {
+// 		return fmt.Errorf("Writing to address %X not implemented!", address)
+// 	}
+// }
diff --git a/gb/console.go b/gb/console.go
index 6397a4a..3e541cc 100644
--- a/gb/console.go
+++ b/gb/console.go
@@ -11,15 +11,19 @@ const (
 )
 
 type Console struct {
+	CPU       *CPU
 	Cartridge *Cartridge
 	front     *image.RGBA
 }
 
 func NewConsole(path string) (*Console, error) {
-	cartridge := InsertCartridge(path)
+	cartridge, err := InsertCartridge(path)
+	if err != nil {
+		return &Console{}, err
+	}
 	buffer := image.NewRGBA(image.Rect(0, 0, ConsoleWidth, ConsoleHeight))
 
-	console := Console{Cartridge: cartridge, front: buffer}
+	console := Console{Cartridge: cartridge, CPU: NewCPU(), front: buffer}
 
 	return &console, nil
 }
diff --git a/gb/cpu.go b/gb/cpu.go
new file mode 100644
index 0000000..d6d1ac8
--- /dev/null
+++ b/gb/cpu.go
@@ -0,0 +1,45 @@
+package gb
+
+const CPUFrequency = 4194304
+
+type Registers struct {
+	A  byte
+	F  byte
+	B  byte
+	C  byte
+	D  byte
+	E  byte
+	H  byte
+	L  byte
+	PC uint16
+	SP uint16
+}
+
+type CPU struct {
+	Regs                Registers
+	FetchedData         uint16
+	MemoryDestination   uint16
+	DestinationIsMemory bool
+	CurrentOPcode       byte
+	// CurrentInstruction     *Instruction
+	Halted                 bool
+	Stepping               bool
+	InterruptMasterEnabled bool
+}
+
+func NewCPU() *CPU {
+	cpu := CPU{}
+	cpu.Regs = Registers{}
+	cpu.Stepping = true
+
+	return &cpu
+}
+
+func (cpu *CPU) Step() bool {
+	if cpu.Stepping {
+		cpu.Stepping = false
+		return true
+	}
+
+	return false
+}
diff --git a/main.go b/main.go
index 4f5a35e..da822d5 100644
--- a/main.go
+++ b/main.go
@@ -1,9 +1,15 @@
 package main
 
 import (
-	"gb-player/ui"
+	"fmt"
+	"log"
+
+	// "gb-player/ui"
+	"gb-player/gb"
 )
 
+var running = true
+
 func main() {
 	// FIXME(m): Allow specifying rom file on command line
 	// if len(os.Args) != 2 {
@@ -12,5 +18,20 @@ func main() {
 	// romPath := os.Args[1]
 	romPath := "./roms/dmg-acid2.gb"
 
-	ui.Run(romPath)
+	// ui.Run(romPath)
+
+	console, err := gb.NewConsole(romPath)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	running := true
+	for running {
+		if !console.CPU.Step() {
+			fmt.Println("CPU stopped")
+			running = false
+		} else {
+			fmt.Println("CPU step")
+		}
+	}
 }
diff --git a/ui/view.go b/ui/view.go
index d27d0d9..c09ab00 100644
--- a/ui/view.go
+++ b/ui/view.go
@@ -22,8 +22,7 @@ func (view *View) Update(dt uint64) {
 	console := view.console
 	renderer := view.controller.renderer
 
-	// console.StepMilliSeconds(dt)
-	console.StepMilliSeconds(sdl.GetTicks64())
+	console.StepMilliSeconds(dt)
 
 	buffer := console.Buffer()