diff --git a/schaltungen/displayboard_servo/software/src/main.c b/schaltungen/displayboard_servo/software/src/main.c
index 36cf47f..4daecea 100644
--- a/schaltungen/displayboard_servo/software/src/main.c
+++ b/schaltungen/displayboard_servo/software/src/main.c
@@ -8,6 +8,8 @@
 #include "main.h"
 #include "uart.h"
 
+#define POWER_MIN	0
+#define POWER_MAX	400
 
 #define BUFSIZE		32
 
@@ -27,16 +29,18 @@ typedef struct {
 } PWR_DATA;
 
 static PWR_DATA pd;
-
 uint8_t data_count = 0;
 char data_in[BUFSIZE];
-extern unsigned char __heap_start;
    
+void reset_input_buffer(void) {
+	data_count = 0;
+	memset(data_in, 0, BUFSIZE);
+}
    
 static void timer_init(void) {
 	// clock is 8MHz
 	TCCR1B |= _BV(WGM12) | _BV(CS11) | _BV(CS10);       // CTC Mode for Timer 1 (16Bit) with prescale of 64
-    OCR1A = 2312;                           // Neutralposition ((2500-2312)*0.008ms)=1,5ms)
+    OCR1A = 2250;                           // Neutralposition ((2500-2312)*0.008ms)=1,5ms)
 	TIMSK = _BV(OCIE1A);
 	TCCR1A = (1<<COM1A0);                   // Togglen bei Compare Match
 }
@@ -61,12 +65,6 @@ static void process_command(char *command) {
         token = strtok(command, ","); 
         
         while( token ) {
-			/*uart_puts_P("\r\ntoken: ");
-			uart_puts(token);
-			
-			uart_puts_P("\r\ntokencounter: ");
-			uart_print_uint16(tokencounter);*/
-			
             switch(tokencounter) {
                 case 0:
                     pd.voltage_gen = atoi(++token);	// skip the A in front of the number
@@ -122,30 +120,29 @@ static void work_uart() {
 		*/
 
         if (data_in[data_count] == 'B') {
-			//uart_puts_P("got b\r\n");
-            
             process_command(data_in);
             
-            data_count = 0;
-            memset(data_in, 0, BUFSIZE);
+            reset_input_buffer();
         } 
         
         data_count++;
 		if(data_count >= BUFSIZE) {
-			data_count = 0;
-			memset(data_in, 0, BUFSIZE);
-			//uart_puts_P("overflow\r\n");
-		}
-        
+			reset_input_buffer();
+		}   
     }
-
-
 }
 
-static void set_servo(uint16_t display) {
+/**
+ *	\brief	set the servo to a position calculated to given power
+ * 
+ * 	\param	display 	The power value from 0 to 400 (including bounds)
+ */
+void set_servo(uint16_t display) {
 
-	if( display < 1 ) display = 1;
-	if( display > 400 ) display = 400;
+	if( display < 1 ) display = POWER_MIN;
+	if( display > POWER_MAX ) display = POWER_MAX;
+
+	display = POWER_MAX-display;	  // invert the value / servo
 
     display = display * 10;   // shift, since we have to divide by 3,2 (32)
     display = display / 32;   // instead of dividing by 3,2
@@ -159,49 +156,41 @@ static void set_servo(uint16_t display) {
 }
 
 
-static void demo_display(void) {
-	for(uint16_t i = 0; i<= 40;i++) {
-		set_servo(i*10);
-		_delay_ms(50);
-	}
-	for(uint16_t i = 40; i> 0;i--) {
-		set_servo(i*10);
-		_delay_ms(50);
-	}
+/**
+ * \brief	the method moves the servo one complete cycle
+ */
+void demo_display(void) {
+	set_servo(0);
+	wait(100);
+	set_servo(400);
+	wait(100);
+	set_servo(0);
+	wait(100);
 }
 
 
 int main(void) {
+	
 	sei();
 	ports_init();
 	timer_init();
     uart_init(UART_BAUD_SELECT(38400,F_CPU));
-    memset(data_in, 0, BUFSIZE);
-    
+    reset_input_buffer();
 	demo_display();
+	
+	uint32_t power;
 
 	while(1) {
-		
 	    work_uart();
 
-        if(syscounter >= 100) {
+        if(syscounter >= 100) {	// about every two seconds
 			memset(data_in, 0, BUFSIZE);
 			data_count = 0;
-            uart_putc('a'); // send a to receive values
-			
-			//uart_puts_P("RAM="); uart_print_uint16(SP - (uint16_t) &__heap_start); uart_puts_P("\r\n");
+            uart_putc('a'); 	// send a to receive values from master box
+			       
+			power = ( (pd.voltage_gen / 100) * (pd.current_gen / 100) ) / 100;      
+            set_servo(power & 0xffff);
             
-            set_servo((pd.voltage_gen/1000) * (pd.current_gen/1000));
-            
-            /*
-            uart_puts_P("voltage_gen = ");
-            uart_print_voltage(pd.voltage_gen);
-            uart_puts_P(" voltage_reg = ");
-            uart_print_voltage(pd.voltage_reg);
-            uart_puts_P(" current_gen = ");
-            uart_print_current(pd.current_gen);
-            uart_puts_P("\r\n");
-            */
             syscounter = 0;
         }
 	}
@@ -209,7 +198,11 @@ int main(void) {
 	return(0);
 }
 
-SIGNAL(TIMER1_COMPA_vect) {
+/**
+ * \brief	this is our timer for PWM generation and system clock
+ * 			the system clock varies a bit, but this does not matter
+ */
+ISR(TIMER1_COMPA_vect) {
 	syscounter++;
     OCR1A = 2500-OCR1A;         // Das Servosignal wird aus der Differenz von
                                 // Periodenlänge (2500*0,008ms=20ms) und letztem