diff --git a/firmware/slider/SliderCommunication b/firmware/slider/SliderCommunication
index 3141a62..362c654 160000
--- a/firmware/slider/SliderCommunication
+++ b/firmware/slider/SliderCommunication
@@ -1 +1 @@
-Subproject commit 3141a62e62012dee60192e6ad1c95ee5b63fc8ce
+Subproject commit 362c65440c49e09e06e89299d51a25003e9724a0
diff --git a/firmware/slider/adc.c b/firmware/slider/adc.c
index 1e978fe..439796a 100644
--- a/firmware/slider/adc.c
+++ b/firmware/slider/adc.c
@@ -12,56 +12,25 @@
 #include <avr/interrupt.h>
 
 // global adc instance
-volatile adc_t adc;
-
-static inline void adc_next() {
-	do {
-		adc.current_channel = (adc.current_channel+1)%8;
-
-		if (!adc.current_channel) {
-			adc.current_sample = adc.buffer.ptr-1;
-		}
-	} while(!(adc.channel_mask & (1<<adc.current_channel)));
-
-	if (adc.current_sample < (adc.buffer.ptr + adc.buffer.size)) {
-		adc.current_sample++;
-	}
-
-	// set mux input
-	ADMUX = adc.current_channel;
-}
+adc_t adc;
 
 /* adc driver */
-void adc_init(adc_buffer_t buffer, uint8_t mask) {
-	if (!mask) {
-		return;
-	}
-
-	adc.buffer = buffer;
-	adc.current_sample = adc.buffer.ptr;
-	adc.channel_mask = mask;
+void adc_init(uint8_t * channels) {
 	adc.current_channel = 0;
+	adc.channel_map = channels;
 
-	// find first channel
-	while(!((1<<adc.current_channel) & mask)) {
-		adc.current_channel++;
+	ADMUX = channels[0];
+	ADCSRA = (1<<ADATE) | (1<<ADEN) | 7; // enable adc, maximum prescaler value
+}
+
+ISR(ADC_vect) {
+	adc.buffer[adc.current_channel] = ADC;
+	adc.current_channel++;
+
+	if (adc.current_channel == ADC_BUFFER_SIZE) {
+		adc.current_channel = 0;
 	}
 
-	ADMUX  = 0;
-	ADCSRA = (1<<ADATE) | (1<<ADEN) | 5 ; // enable adc, maximum prescaler value
-}
-
-void adc_start() {
-	ADCSRA |= (1<<ADIE) | (1<<ADSC); // enable adc interrupt
-}
-
-void adc_stop( ){
-	ADCSRA &= ~(1<<ADIE);
-}
-
-#include "led.h"
-ISR(ADC_vect) {
-	**adc.current_sample = ADC;
-	adc_next();
+	ADMUX = adc.channel_map[adc.current_channel];
 }
 
diff --git a/firmware/slider/adc.h b/firmware/slider/adc.h
index cc9cb1a..024fd82 100644
--- a/firmware/slider/adc.h
+++ b/firmware/slider/adc.h
@@ -12,38 +12,25 @@
 
 typedef uint16_t adc_sample_t;
 
+#define ADC_BUFFER_SIZE 5
+
 typedef struct {
-	adc_sample_t ** ptr;
-	uint8_t size;
+
 } adc_buffer_t;
 
 typedef struct adc {
-	adc_buffer_t buffer;
+	adc_sample_t buffer[ADC_BUFFER_SIZE];
 
-	uint8_t current_channel;
-	adc_sample_t ** current_sample;
-	uint8_t channel_mask;
+	volatile uint8_t current_channel;
+	uint8_t * channel_map;
 } adc_t;
 
 // the adc instance
-extern volatile adc_t adc;
+extern adc_t adc;
 
-enum {
-	ADC_CHANNEL_0 = 0x01,
-	ADC_CHANNEL_1 = 0x02,
-	ADC_CHANNEL_2 = 0x04,
-	ADC_CHANNEL_3 = 0x08,
-	ADC_CHANNEL_4 = 0x10,
-	ADC_CHANNEL_5 = 0x20,
-	ADC_CHANNEL_6 = 0x40,
-	ADC_CHANNEL_7 = 0x80,
-	ADC_CHANNEL_ALL = 0xFF,
-};
+void adc_init(uint8_t * channels);
 
-
-void adc_init(adc_buffer_t buffer, uint8_t channel_mask);
-
-void adc_start();
-void adc_stop();
+#define adc_start() ADCSRA |= (1<<ADIE) | (1<<ADSC)
+#define adc_stop()  ADCSRA &= ~(1<<ADIE)
 
 #endif /* ADC_H_ */
diff --git a/firmware/slider/led.h b/firmware/slider/led.h
index 8a4b3a1..8a9a914 100644
--- a/firmware/slider/led.h
+++ b/firmware/slider/led.h
@@ -15,17 +15,17 @@
 #define LED_REG PORTB
 #define LED_PIN 0
 
-static inline void led_toggle() {
-	LED_REG ^= (1<<LED_PIN);
-}
+#define led_toggle() do {     \
+	LED_REG ^= (1<<LED_PIN);  \
+} while(0)
 
-static inline void led_off() {
-	LED_REG |= (1<<LED_PIN);
-}
+#define led_off() do {        \
+	LED_REG |= (1<<LED_PIN);  \
+} while(0)
 
-static inline void led_on() {
-	LED_REG &= ~(1<<LED_PIN);
-}
+#define led_on() do {         \
+	LED_REG &= ~(1<<LED_PIN); \
+} while(0)
 
 
 void led_init();
diff --git a/firmware/slider/main.c b/firmware/slider/main.c
index 8f51148..1db0ecc 100644
--- a/firmware/slider/main.c
+++ b/firmware/slider/main.c
@@ -12,106 +12,19 @@
 
 #include <interface.h>
 
-typedef struct {
-	byte_t * buffer_start, * buffer_end;
-	
-	volatile byte_t * read;
-	volatile byte_t * write;
-	volatile byte_t count; 
-	
-	iface_t iface;
-} comm_t;
-
-comm_t comm;
-
-void comm_write(iface_t * iface, byte_t byte) {
-	if ((comm.write == comm.read) && comm.count) {
-		// write overflow
-		return;
-	}
-	
-	*comm.write = byte;
-	++comm.count;
-	
-	// advance write pointer
-	if ((++comm.write) >= comm.buffer_end) {
-		comm.write = comm.buffer_start;
-	}
-}
-
-inline byte_t comm_read() {
-	if (!comm.count)
-		return 0x00;
-		
-	byte_t result = *comm.read;
-	
-	--comm.count;
-	if ((++comm.read) >= comm.buffer_end) {
-		comm.read = comm.buffer_start;
-	}
-	
-	return result;
-}
-
-byte_t comm_buffer[10];
-
-void comm_init() 
-{
-	comm.buffer_start = comm_buffer;
-	comm.buffer_end   = comm_buffer + sizeof(comm_buffer);
-	
-	// reset buffer
-	comm.write = comm.buffer_start;
-	comm.read  = comm.buffer_start;
-	comm.count = 0;
-	
-	// TODO: setup pins
-	DDRA |= (1<<PA5); // setup MOSI as output
-	
-	// TODO: setup USART in synchronous mode
-	USICR = (1<<USIWM0)|(1<<USICS1);
-
-	// init interface
-	comm.iface.write   = comm_write;
-	comm.iface.on_read = 0;
-}
-
-void comm_start() 
-{
-	// don't start without interrupt handler
-	if (!comm.iface.on_read)
-		return;
-
-	// TODO: activate USART 
-	USICR |= (1<<USIOIE);
-}
-
-ISR(USI_OVF_vect) 
-{
-	cli();
-	// write buffer out if there is data to be written
-	//if (!comm.count) {
-		// call interrupt handler
-		//comm.iface.on_read(&comm.iface, USIDR, comm.iface.callback_data);
-	//}
-	
-	USIDR = 0x02;
-	sei();
-	//USIDR = comm_read();
-}
-
 #include "main.h"
 
+void comm_init();
+
 // the public instance of the app buffer
 struct app app = {};
 
-adc_sample_t * channel_map[] = {
-	// update app state (remap channels)
-	&app.state.state.poti[2],
-	&app.state.state.poti[3],
-	&app.state.state.poti[1],
-	&app.state.state.poti[0],
-	&app.state.state.slider
+uint8_t channel_map[ADC_BUFFER_SIZE] = {
+	0,
+	1,
+	2,
+	3,
+	7
 };
 
 // initalizes the application modules
@@ -124,25 +37,80 @@ void init()
 	// init adc module
 	// will sample 0x8F (CHANNEL 8 and 0-3) 
 	// this module also updates app.buffer.poti and slider for us
-	adc_init((adc_buffer_t){
-		.ptr  = channel_map,
-		.size = sizeof(channel_map),
-	}, 0x8F);
+	adc_init(channel_map);
 
 	// init communication module
 	comm_init();
 	
-	// bind state encoder to communication module
-	slave_init(&app.state, &comm.iface);
-	
 	// start all modules
 	adc_start();
-	comm_start();
-	
+
 	// activate interrupts (effectivly starting the application)
 	sei();
 }
 
+void comm_init()
+{
+	DDRA |= (1<<PA5); // setup MOSI as output
+	USICR = (1<<USIWM0)|(1<<USICS1);
+}
+
+volatile enum {
+	COMM_WAIT       = 0,
+	COMM_SEND_START ,
+	COMM_SEND_WAIT  ,
+	COMM_SEND_END   ,
+} comm_state;
+
+static inline void comm_service()
+{
+	static uint8_t count = 0;
+	static uint16_t temp = 0xFF;
+
+	if (USISR & (1<<USIOIF))
+	{
+		led_on();
+		cli();
+
+		switch(comm_state)
+		{
+		case COMM_WAIT:
+			if (IS_EOM(USIDR)) {
+				// pass package through
+				USIDR &= ~0x80;
+				comm_state = COMM_SEND_START;
+				adc_stop();
+			}
+			break;
+		case COMM_SEND_START:
+			temp = adc.buffer[count];
+			USIDR = temp & 0x7F;
+			comm_state = COMM_SEND_WAIT;
+			break;
+		case COMM_SEND_WAIT:
+			USIDR = (temp>>7)&0x7F;
+
+			if (++count == ADC_BUFFER_SIZE) {
+				comm_state = COMM_SEND_END;
+			} else {
+				comm_state = COMM_SEND_START;
+			}
+			break;
+		case COMM_SEND_END:
+			count = 0;
+			USIDR = app.state.state.button | 0x80;
+		default:
+			comm_state = COMM_WAIT;
+			adc_start();
+			break;
+		}
+
+		USISR |= (1<<USIOIF);
+
+		sei();
+		led_off();
+	}
+}
 #include <util/delay.h>
 
 // little debug helper function
@@ -158,8 +126,10 @@ void delay(uint16_t d)
 int main() 
 {
 	init();
-	
+
 	while(1) {
-		// nothing to do here, the application is interrupt-driven
+		// service serial interface
+		// slightly more stable then interrupt
+		comm_service();
 	}
 }