diff --git a/firmware.asm b/firmware.asm
index ecfb280..7daf0c3 100644
--- a/firmware.asm
+++ b/firmware.asm
@@ -15,8 +15,8 @@
 
 ;
 ; Registers
-.def temp_r = r16
-.def mcu_state_r = r17
+.def temp_r = r16           ; General register A.
+.def mcu_state_r = r17      ; Current state of MCU. This register will be compared in an main loop.
 
 ;
 ; LEDS constants
@@ -70,7 +70,7 @@
 .org	SRAM_START
 
 ;
-; MCU Global states
+; MCU Global states addresses
 CURRENT_STATE_ADDRESS:  .byte	0x01
 PREVIOUS_STATE_ADDRESS: .byte 0x01
 
@@ -129,12 +129,12 @@ loop:                       ; Program loop
     cpi mcu_state_r, INIT_STATE
     brne showing
     rcall MCU_Init
-    set_state SHOWING_STATE 
+    set_state SHOWING_STATE
   showing:                  ; Showing state
     cpi mcu_state_r, SHOWING_STATE
     brne polling
     rcall show_sequence
-    ; set_state POLLING_STATE
+    set_state POLLING_STATE
   polling:                  ; Polling state
     cpi mcu_state_r, POLLING_STATE
     brne completion
@@ -145,7 +145,7 @@ loop:                       ; Program loop
       brne led_off_1
       led_on_1:
         sbi LED_PORT, 0
-        sbi BUZZ_DIR, BUZZ_PIN
+        ; buzzer_on
         outi OCR0A, 142
         rjmp led_2
       led_off_1:
@@ -155,7 +155,7 @@ loop:                       ; Program loop
       brne led_off_2
       led_on_2:
         sbi LED_PORT, 1
-        sbi BUZZ_DIR, BUZZ_PIN
+        ; buzzer_on
         outi OCR0A, 71
         rjmp led_3
       led_off_2:
@@ -165,7 +165,7 @@ loop:                       ; Program loop
       brne led_off_3
       led_on_3:
         sbi LED_PORT, 2
-        sbi BUZZ_DIR, BUZZ_PIN
+        ; buzzer_on
         outi OCR0A, 105
         rjmp led_4
       led_off_3:
@@ -175,7 +175,7 @@ loop:                       ; Program loop
       brne led_off_4
       led_on_4:
         sbi LED_PORT, 3
-        sbi BUZZ_DIR, BUZZ_PIN
+        ; buzzer_on
         outi OCR0A, 80
         rjmp polling
       led_off_4:
@@ -186,7 +186,7 @@ loop:                       ; Program loop
   default:                  ; Do nothing
 rjmp loop
 
-show_sequence:              ; Show sequence of led
+show_sequence:              ; Generate sequence of leds and store in SRAM and then set POLLING state
   nop
 ret
 
@@ -239,6 +239,7 @@ MCU_Init:
   rcall init_interrupts
   rcall init_buzzer
   rcall delay_before_start  ; Init MCU and delay before start main program
+  sei                       ; Enable Global Interrupts
 ret
 
 delay_before_start:
@@ -247,7 +248,7 @@ delay_before_start:
     rcall effect_1
     dec temp_r
     brne _init_loop_loading
-  rcall delay_1s
+  rcall delay_1s            ; Wait 1 sec before start main program
   clr temp_r
 ret
 
@@ -263,8 +264,6 @@ init_interrupts:
   out PCMSK0, temp_r
 
   clr temp_r
-
-  sei                       ; Enable Global Interrupts
 ret
 
 init_buzzer:
@@ -279,7 +278,6 @@ init_buzzer:
 
   ldi temp_r, (1<<CS01)                       ; Prescale on 8
   out TCCR0B, temp_r
-
 ret
 
 init_ports:                 ; Init MCU ports
diff --git a/firmware.hex b/firmware.hex
index 794168b..152d01d 100644
--- a/firmware.hex
+++ b/firmware.hex
@@ -1,31 +1,31 @@
 :020000020000FC
 :100000001CC018950EC01895189518951895189538
 :100010001895189518951895189518951895189578
-:1000200018951F932F932FB719B3107F98D0109363
-:1000300062002FBF2F911F9118950FED0DBF1093E8
-:1000400061000F9301E0009360000F911091600038
-:10005000113041F462D0109361000F9302E00093DD
-:1000600060000F91123009F42FD0133051F5209118
-:100070006200203E39F4D89ABA9A0F930EE806BF70
-:100080000F9101C0D898203D39F4D99ABA9A0F93AC
-:1000900007E406BF0F9101C0D998203B39F4DA9AE2
-:1000A000BA9A0F9309E606BF0F9101C0DA9820377C
-:1000B00039F4DB9ABA9A0F9300E506BF0F91D5CFBA
-:1000C000DB98143001F4C2CF000008951F932F93E2
-:1000D0003F934F934BB30F9301EF0BBB0F913FD067
-:1000E00011E033E020EF110F210F2BBB38D03A95F0
-:1000F000C9F70F9308EF0BBB0F9131D018E033E035
-:1001000020EF1695210F2BBB2AD03A95C9F74BBB90
-:100110004F913F912F911F9108951AD00AD010D07E
-:1001200001D0089506E0D2DF0A95E9F724D0002730
-:10013000089500E10BBF00EF02BB002778940895FB
-:10014000BA9802E400BF0EE006BF02E003BF0895C4
-:100150000FE00ABB02950BBBBA9AC29808952F9381
-:100160003F9321E43FEE3A95F1F72A95E1F700003D
-:100170003F912F9108958F939F9324E683EC99E00C
-:100180000197F1F72A95D1F724E69F918F91089571
-:100190004D656D6F7279206C65642067616D652EA9
-:1001A000205772697474656E206279205365726796
-:1001B0006579205961726B6F762032372E30392E77
-:0401C0003230323176
+:1000200018951F932F932FB719B3107F9CD010935F
+:1000300062002FBF2F911F9118950FED0DBF002764
+:10004000109361000F9301E0009360000F911091F5
+:100050006000113041F465D0109361000F9302E00D
+:10006000009360000F91123041F432D01093610080
+:100070000F9303E0009360000F91133031F520914E
+:100080006200203E31F4D89A0F930EE806BF0F911C
+:1000900001C0D898203D31F4D99A0F9307E406BFE8
+:1000A0000F9101C0D998203B31F4DA9A0F9309E6F9
+:1000B00006BF0F9101C0DA98203731F4DB9A0F9315
+:1000C00000E506BF0F91D9CFDB98143001F4BFCF04
+:1000D000000008951F932F933F934F934BB30F93BB
+:1000E00001EF0BBB0F913FD011E033E020EF110F78
+:1000F000210F2BBB38D03A95C9F70F9308EF0BBBF4
+:100100000F9131D018E033E020EF1695210F2BBB73
+:100110002AD03A95C9F74BBB4F913F912F911F9130
+:1001200008951AD00BD010D002D07894089506E02C
+:10013000D1DF0A95E9F723D00027089500E10BBF2E
+:1001400000EF02BB00270895BA9802E400BF0EE05A
+:1001500006BF02E003BF08950FE00ABB02950BBB88
+:10016000BA9AC29808952F933F9321E43FEE3A95AF
+:10017000F1F72A95E1F700003F912F9108958F93B1
+:100180009F9324E683EC99E00197F1F72A95D1F744
+:1001900024E69F918F9108954D656D6F7279206C63
+:1001A00065642067616D652E205772697474656E91
+:1001B00020627920536572676579205961726B6F8F
+:0C01C000762032372E30392E32303231AA
 :00000001FF
diff --git a/macros.asm b/macros.asm
index 4dea419..be71821 100644
--- a/macros.asm
+++ b/macros.asm
@@ -4,9 +4,11 @@
 .macro init_stack_p
   ldi @0, low(@1)
   out SPL, @0
+  clr @0
   .ifdef SPH 
     ldi @0, high(RAMEND) 
     out SPH, @0 
+    clr @0
   .endif
 .endm
 
@@ -15,10 +17,10 @@
 ; @0 - I/O Register
 ; @1 - Data to write
 .macro outi
-  push r16
-  ldi r16, @1
-  out @0, r16
-  pop r16
+  push temp_r
+  ldi temp_r, @1
+  out @0, temp_r
+  pop temp_r
 .endm
 
 ;
@@ -26,10 +28,10 @@
 ; @0 - SRAM Address
 ; @1 - Data to write
 .macro stsi
-  push r16
-  ldi r16, @1
-  sts @0, r16
-  pop r16
+  push temp_r
+  ldi temp_r, @1
+  sts @0, temp_r
+  pop temp_r
 .endm
 
 ;
@@ -38,4 +40,12 @@
 .macro set_state
   sts PREVIOUS_STATE_ADDRESS, mcu_state_r         ; Write previous state to SRAM
   stsi CURRENT_STATE_ADDRESS, @0
+.endm
+
+.macro buzzer_on
+  sbi BUZZ_DIR, BUZZ_PIN
+.endm
+
+.macro buzzer_off
+  cbi BUZZ_DIR, BUZZ_PIN
 .endm
\ No newline at end of file