diff --git a/src/cpu.mpy b/src/cpu.mpy
deleted file mode 100644
index c8dc73d..0000000
--- a/src/cpu.mpy
+++ /dev/null
@@ -1,92 +0,0 @@
-import sys
-
-class CPU:
-  def __init__(self):
-    self.running = False
-    self.IP = 254
-    self.acc = 0
-    self.flags = { 'C': False, 'Z': False, 'N': False, 'Eq': False }
-    self.instruction = { 'opcode': False, 'operand': False }
-    self.memory = False
-
-  def load_memory(self, bytes):
-    self.memory = bytes + bytearray(256 - len(bytes))
-    print('mem 254', self.memory[254])
-    # print(self.memory)
-
-  def start(self):
-    self.running = True
-
-  def step(self):
-    if self.IP >= 256:
-      self.IP = 0
-    print("IP:", self.IP)
-    self.instruction['opcode'] = self.memory[self.IP]
-    self.IP = self.IP+1
-    self.instruction['operand'] = self.memory[self.IP]
-    self.IP = self.IP+1
-    print("instr:", self.instruction['opcode'], self.instruction['operand'])
-    print("mnem:", self.nums2mnems[self.instruction['opcode']])
-    self.nums2mnems[self.instruction['opcode']](self, self.instruction['operand'])
-    print("acc:", self.acc)
-    print("running:", self.running)
-    print()
-    if not self.running:
-      sys.exit()
-
-  def hlt(self, operand):
-    self.running = False
-
-  def nop(self, operand):
-    pass
-
-  def add_lit(self, operand):
-    self.acc = self.acc + operand
-
-  def add_mem(self, operand):
-    self.acc = self.acc + self.memory[operand]
-
-  def jmp_lit(self, operand):
-    self.IP = operand
-
-  nums2mnems = {
-    0: hlt,
-    1: nop,
-    2: 'lda_lit',
-    3: 'sta_lit',
-    4: add_lit,
-    5: 'sub_lit',
-    6: jmp_lit,
-    7: 'ske',
-    8: 'skz',
-    9: 'skn',
-    10: 'skc',
-    11: 'cst',
-    12: 'ccl',
-    16: 'hlt',
-    17: 'nop',
-    18: 'lda_mem',
-    19: 'sta_mem',
-    20: add_mem,
-    21: 'sub_mem',
-    22: 'jmp_mem',
-    23: 'ske',
-    24: 'skz',
-    25: 'skn',
-    26: 'skc',
-    27: 'cst',
-    28: 'ccl',
-  }
-
-cpu = CPU()
-
-prog = '04 01 14 01 00 00'
-program_bytes = bytes.fromhex(prog)
-# Add jmp at addr 254:
-program_with_jump = program_bytes + bytearray(254 - len(program_bytes)) + bytes.fromhex('06 00')
-cpu.load_memory(program_with_jump)
-
-cpu.start()
-cpu.step()
-cpu.step()
-cpu.step()
diff --git a/src/cpu.py b/src/cpu.py
index 7da5078..d9c8b92 100644
--- a/src/cpu.py
+++ b/src/cpu.py
@@ -1,4 +1,5 @@
-import sys
+from sys import exit
+from time import sleep
 
 class CPU:
     def __init__(self):
@@ -11,6 +12,7 @@ class CPU:
 
     def load_memory(self, bytes):
         self.memory = bytes + bytearray(256 - len(bytes))
+        print(type(self.memory))
         print('mem 254', self.memory[254])
         # print(self.memory)
 
@@ -29,7 +31,21 @@ class CPU:
                     print("_", end="  ")
             print()
 
+    def read_keys(self):
+        key = input(">").upper()
+        if self.running:
+            if key in ['1', '2', '3', '4', '5', '6', '7', '8', '9', '0']:
+                print(type(self.memory))
+                self.memory[26] = int(key)
+            if key in ['A', 'B', 'C', 'D', 'E', 'F']:
+                 self.memory[26] = ord(key) - 55
+            if key == "H": # halt
+                self.running = False
+        else:
+            # TODO trainer interface
+
     def step(self):
+        self.read_keys()
         if self.IP >= 256:
             self.IP = 0
         print("IP:", self.IP)
@@ -44,9 +60,16 @@ class CPU:
         print("running:", self.running)
         print()
         self.print_screen()
+        print("byte 26 (keyboard):", self.memory[26])
         print()
-        if not self.running:
-            sys.exit()
+        # if not self.running:
+            # exit()
+
+    def run(self):
+        self.start()
+        while True:
+            self.step()
+            sleep(0.1)
 
     def hlt(self, operand):
         self.running = False
@@ -170,16 +193,12 @@ class CPU:
 cpu = CPU()
 
 prog = '04 FF 04 01 14 01 00 00'
-program_bytes = bytes.fromhex(prog)
+program_bytes = bytearray.fromhex(prog)
 # Add jmp at addr 254:
-program_with_jump = program_bytes + bytearray(254 - len(program_bytes)) + bytes.fromhex('06 00')
+program_with_jump = program_bytes + bytearray(254 - len(program_bytes)) + bytearray.fromhex('06 00')
 cpu.load_memory(program_with_jump)
 
-cpu.print_screen()
+# cpu.start()
+# cpu.step()
 
-cpu.start()
-cpu.step()
-cpu.step()
-cpu.step()
-cpu.step()
-cpu.step()
+cpu.run()