diff --git a/LedCube/FrameBuffer.cpp b/LedCube/FrameBuffer.cpp
index 157f6de..d94793b 100644
--- a/LedCube/FrameBuffer.cpp
+++ b/LedCube/FrameBuffer.cpp
@@ -256,9 +256,6 @@ struct FrameBuffer {
 } FrameBuffer;
 #endif
 
-extern char position2pin[MAX_X][MAX_Y];
-extern char layer[MAX_Z];
-
 void FrameBufferSwitch(void) {
 #if FRAMEBUFFER_POINTERS
   Frame * t = FrameBuffer.back;
@@ -285,20 +282,24 @@ static Frame *FrameBufferGetBack(void) {
 #endif
 }
 
-void FrameBufferReadFront(char x, char y, char z, unsigned char *val) {
+void FrameBufferReadFront(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char *val) {
   *val = FrameBufferGetFront()->data[x][y][z];
 }
 
-void FrameBufferReadBack(char x, char y, char z, unsigned char *val) {
+void FrameBufferReadBack(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char *val) {
   *val = FrameBufferGetBack()->data[x][y][z];
 }
 
-void FrameBufferCopy(char x1, char y1, char z1, char x2, char y2, char z2) {
+void FrameBufferCopy(unsigned char x1, unsigned char y1, unsigned char z1,
+        unsigned char x2, unsigned char y2, unsigned char z2) {
   FrameBufferGetBack()->data[x1][y1][z1] =
     FrameBufferGetFront()->data[x2][y2][z2];
 }
 
-void FrameBufferWrite(char x, char y, char z, unsigned char val) {
+void FrameBufferWrite(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char val) {
   FrameBufferGetBack()->data[x][y][z] = val;
 }
 
@@ -306,14 +307,14 @@ void FrameBufferSet(unsigned char val) {
   memset(FrameBufferGetBack(), val, FRAME_SIZE());
 }
 
-void FrameBufferBlank() {
+void FrameBufferBlank(void) {
   FrameBufferSet(0);
 }
 
-static void letter(char l, char brightness) {
+static void letter(unsigned char l, unsigned char brightness) {
   memset(FrameBufferGetBack(), 0, FRAME_SIZE());
-  for (char x = 0; x < MAX_X; x++) {
-    for (char y = 0; y < MAX_Y; y++) {
+  for (unsigned char x = 0; x < MAX_X; x++) {
+    for (unsigned char y = 0; y < MAX_Y; y++) {
       FrameBufferGetBack()->data[3][y][3-x] =
         font[l - 'a'][x][y] * brightness;
     }
@@ -322,16 +323,16 @@ static void letter(char l, char brightness) {
   delay(200);
 }
 
-void printAllSymbols() {
-  for(char c = 0; c < sizeof(font)/sizeof(font[0]); c++) {
+void printAllSymbols(void) {
+  for(unsigned char c = 0; c < sizeof(font)/sizeof(font[0]); c++) {
     letter(c+'a', 127);
     delay(500);
   }
 }
 
-void FrameBufferWriteStr(char * str, const short delayPerLetter, 
+void FrameBufferWriteStr(char const * str, const short delayPerLetter, 
         const unsigned char brightness) {
-  unsigned char *c = str;
+  char const *c = str;
   while(*c != 0) {
     if (*c == ' ') {
       memset(FrameBufferGetBack(), 0, FRAME_SIZE());
@@ -351,7 +352,13 @@ void FrameBufferWriteStr(char * str, const short delayPerLetter,
   }
 }
 
-void FrameBufferRefresh(void) {
+
+static void FrameBufferRefresh(void) {
+#if DEBUG_FB_REFRESH
+  static long int timeStartRefresh = micros();
+  static long int timeLastRefresh = 0;
+#endif
+
   Frame *f = FrameBufferGetFront();
 #if BRIGHTNESS_INCREMENT
   FrameBuffer.intensity = 
@@ -360,15 +367,10 @@ void FrameBufferRefresh(void) {
   FrameBuffer.intensity = 128;
 #endif
 
-#if DEBUG_FB_REFRESH
-  static int timeStartRefresh = micros();
-  static int timeLastRefresh = 0;
-#endif
-
-  for (char z = 0; z < MAX_Z; z++) {
+  for (unsigned char z = 0; z < MAX_Z; z++) {
     // 1. Set up the layer leds to be turned on / off
-    for (char x = 0; x < MAX_X; x++) {
-      for (char y = 0; y < MAX_Y; y++) {
+    for (unsigned char x = 0; x < MAX_X; x++) {
+      for (unsigned char y = 0; y < MAX_Y; y++) {
         if (f->data[x][y][z] > FrameBuffer.intensity) {
           digitalWrite(position2pin[x][y], HIGH);
         } else {
@@ -404,15 +406,15 @@ void FrameBufferRefresh(void) {
 
 void FrameBufferInit(void) {
   // Setting rows to ouput
-  for (char x = 0; x < MAX_X; x++) {
-    for (char y = 0; y < MAX_Y; y++) {
+  for (unsigned char x = 0; x < MAX_X; x++) {
+    for (unsigned char y = 0; y < MAX_Y; y++) {
       pinMode(position2pin[x][y], OUTPUT);
       digitalWrite(position2pin[x][y], LOW);
     }
   }
 
   // Setting layers to output
-  for (char z = 0; z < MAX_Z; z++) {
+  for (unsigned char z = 0; z < MAX_Z; z++) {
     pinMode(layer[z], OUTPUT);
     digitalWrite(layer[z], HIGH);
   }
diff --git a/LedCube/FrameBuffer.h b/LedCube/FrameBuffer.h
index ee9ece0..2102d57 100644
--- a/LedCube/FrameBuffer.h
+++ b/LedCube/FrameBuffer.h
@@ -32,9 +32,8 @@
  */
 
 /* Either 1 (Enabled) or 0 (disabled) */
-#define DEBUG 0
 #if DEBUG
-#define DEBUG_FB_REFRESH 1
+#define DEBUG_FB_REFRESH 0
 #endif
 
 /* All the code assumes dimensions are below 127, as signed chars are used to
@@ -71,19 +70,22 @@ void FrameBufferSwitch(void);
  * Read the brightness ``val'' of the led at position (x,y,z), in the front
  * buffer.
  */
-void FrameBufferReadFront(char x, char y, char z, unsigned char *val);
+void FrameBufferReadFront(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char *val);
 
 /**
  * Read the brightness ``val'' of the led at position (x,y,z), in the back
  * buffer.
  */
-void FrameBufferReadBack(char x, char y, char z, unsigned char *val);
+void FrameBufferReadBack(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char *val);
 
 /**
  * Copy the value from (x2, y2, z2) in the front buffer, to (x1,y1,z1) in
  * the back buffer.
  */
-void FrameBufferCopy(char x1, char y1, char z1, char x2, char y2, char z2);
+void FrameBufferCopy(unsigned char x1, unsigned char y1, unsigned char z1,
+        unsigned char x2, unsigned char y2, unsigned char z2);
 
 /**
  * Write the brightness ``val'' to the led at position (x,y,z), in the back
@@ -92,7 +94,8 @@ void FrameBufferCopy(char x1, char y1, char z1, char x2, char y2, char z2);
  * In order to make the value visible, a call to FrameBufferSwitch is needed,
  * once the drawing of the frame is complete.
  */
-void FrameBufferWrite(char x, char y, char z, unsigned char val);
+void FrameBufferWrite(unsigned char x, unsigned char y, unsigned char z,
+        unsigned char val);
 
 /**
  * Write the brightness ``val'' to the whole back buffer.
@@ -108,7 +111,7 @@ void FrameBufferSet(unsigned char val);
  * In order to make the value visible, a call to FrameBufferSwitch is needed,
  * once the drawing of the frame is complete.
  */
-void FrameBufferBlank();
+void FrameBufferBlank(void);
 
 /**
  * Print the string, a letter at a time, showing each for delayPerLetter time,
@@ -117,7 +120,7 @@ void FrameBufferBlank();
  * This has minimal checks, only lowercase font, space and zero to terminate
  * the string.
  */
-void FrameBufferWriteStr(char * str, const short delayPerLetter, 
+void FrameBufferWriteStr(char const * str, const short delayPerLetter, 
         const unsigned char brightness);
 
 /**
@@ -125,11 +128,6 @@ void FrameBufferWriteStr(char * str, const short delayPerLetter,
  */
 void printAllSymbols(void);
 
-/** 
- * Draw the front frame on the ``screen''.
- */
-void FrameBufferRefresh(void);
-
 /** 
  * Initialize the framebuffer, and start the timer to refresh the ``screen''.
  */
diff --git a/LedCube/LedCube.ino b/LedCube/LedCube.ino
index 9276822..3381e74 100644
--- a/LedCube/LedCube.ino
+++ b/LedCube/LedCube.ino
@@ -47,14 +47,14 @@
 
 /* Either 1 (Enabled) or 0 (disabled) */
 #define DEBUG 0 
+
+#include "FrameBuffer.h"
+
 #if DEBUG
 #define DEBUG_SETUP 1
 #define DEBUG_LOOP 1
 #endif
 
-#include "FrameBuffer.h"
-
-
 /******************************* ANIMATIONS ********************************/
 
 /* Taken from PWMallPins.pde by Paul Badger, 2007;
@@ -165,17 +165,17 @@ void sine2(int period /* [ms] */) {
 void sine3(int period /* [ms] */) {
   for(int i = 0; i < 256; i++) {
     FrameBufferBlank();;
-    for (char x = 1; x < 3; x++) {
-      for (char y = 1; y < 3; y++) {
-        for (char z = 1; z < 3; z++) {
+    for (unsigned char x = 1; x < 3; x++) {
+      for (unsigned char y = 1; y < 3; y++) {
+        for (unsigned char z = 1; z < 3; z++) {
           FrameBufferWrite(x, y, z, sinewave[i]);
         }
       }
     }
 
-    for (char x = 0; x < MAX_X; x++) {
-      for (char y = 0; y < MAX_Y; y++) {
-        for (char z = 0; z < MAX_Z; z++) {
+    for (unsigned char x = 0; x < MAX_X; x++) {
+      for (unsigned char y = 0; y < MAX_Y; y++) {
+        for (unsigned char z = 0; z < MAX_Z; z++) {
           if ( ((x == 0) || (x == 3))
              ||((y == 0) || (y == 3))
              ||((z == 0) || (z == 3))) {
@@ -193,12 +193,11 @@ void sine3(int period /* [ms] */) {
 /**
  * Random rain drpos fall to the bottom of the cube
  */
-void randomRain() {
-  unsigned char val;
-  for (char a = MAX_Z; a > 0; a--) {
+void randomRain(void) {
+  for (unsigned char a = MAX_Z; a > 0; a--) {
     // animation of 4 steps, requiring computing 4 full frames
-    for (char x = 0; x < MAX_X; x++) {
-      for (char y = 0; y < MAX_Y; y++) {
+    for (unsigned char x = 0; x < MAX_X; x++) {
+      for (unsigned char y = 0; y < MAX_Y; y++) {
           FrameBufferWrite(x, y, 3,
             (random(0, 4) == 0) ? 1 : random(0, BRIGHTNESS_MAX));
           FrameBufferCopy(x, y, 2, x, y, 3);
@@ -214,7 +213,7 @@ void randomRain() {
 
 /********************************** BODY ***********************************/
 
-void setup()
+void setup(void)
 {
 #if DEBUG_SETUP
   static long timeStartSetup = micros();
@@ -223,20 +222,19 @@ void setup()
   // Seeding random for random pattern
   randomSeed(analogRead(10));
 
+  FrameBufferInit();
+
 #if DEBUG
   Serial.begin(9600);
   Serial.println("\nSetup DONE");
 #endif
-
-  FrameBufferInit();
-
 #if DEBUG_SETUP
   Serial.print("Setup Time: ");
   Serial.println((micros() - timeStartSetup), DEC);
 #endif
 }
 
-void loop() {
+void loop(void) {
   static char a = -1;
 
 #if DEBUG_LOOP
@@ -261,7 +259,6 @@ void loop() {
     }
   }
 
-
 #if DEBUG_LOOP
   Serial.print("Loop Time: ");
   Serial.println((micros() - timeStartLoop), DEC);