diff --git a/firmware/Makefile b/firmware/Makefile
index 9a0f19f..c805113 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -35,7 +35,7 @@ OPT = s
 
 ##########################################################################################################
 # List C source files here. (C dependencies are automatically generated.)
-SRC	= main.c synth.c
+SRC	= main.c synth.c usart.c
 ##########################################################################################################
 
 
diff --git a/firmware/main.c b/firmware/main.c
index 04da2ca..8f91f70 100644
--- a/firmware/main.c
+++ b/firmware/main.c
@@ -6,7 +6,7 @@
 
 #include "main.h"
 #include "synth.h"
-
+#include "usart.h"
 
 static void init_sampletimer(void)
 {
@@ -74,6 +74,7 @@ int main(void)
 {
 	/* hardware initialisation: */
 	init_leds();
+	USART0_Init();
 	// init_motor();
 	init_pwm();
 	init_sampletimer();
@@ -94,5 +95,7 @@ ISR(TIMER0_COMPA_vect)
 {
 	/* calculate next analog sample value in synth mixer:*/
 	OCR1B = synth_mix();
+	USART0_put_uint16(0x1234);
+	USART0_crlf();
 }
 
diff --git a/firmware/usart.c b/firmware/usart.c
new file mode 100644
index 0000000..0937238
--- /dev/null
+++ b/firmware/usart.c
@@ -0,0 +1,132 @@
+/*
+ * PentaFnord Firmware
+ *
+ * by Alexander Lorz <bigalex@gmx.de>
+ *
+ *
+ * The USART control code is derived by code from the 4CHLED project
+ * by sebseb7: https://github.com/sebseb7/eagle/tree/master/4CHLED/firmware
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+//#include "main.h"
+#include "usart.h"
+
+#define UART_RXBUFSIZE 32
+
+volatile static uint8_t rxbuf0[UART_RXBUFSIZE];
+volatile static uint8_t *volatile rxhead0, *volatile rxtail0;
+//volatile uint8_t xon = 0;
+
+
+ISR (USART_RX_vect)
+{
+	UCSR0B &= ~(1 << RXCIE0);
+	asm volatile("sei");
+
+	int diff;
+	uint8_t c;
+	c=UDR0;
+	diff = rxhead0 - rxtail0;
+	if (diff < 0) diff += UART_RXBUFSIZE;
+	if (diff < UART_RXBUFSIZE -1)
+	{
+		*rxhead0 = c;
+		++rxhead0;
+		if (rxhead0 == (rxbuf0 + UART_RXBUFSIZE)) rxhead0 = rxbuf0;
+//		if((diff > 100)&&(xon==0))
+//		{
+//			xon=1;
+//			//set the CTS pin
+//		}
+	}
+	UCSR0B |= (1 << RXCIE0);
+}
+
+
+void USART0_Init (void)
+{
+	// set baudrate
+		#undef BAUD
+		#define BAUD 115200
+		#include <util/setbaud.h><util/setbaud.h>
+		UBRR0H = UBRRH_VALUE;
+		UBRR0L = UBRRL_VALUE;
+
+	//#if USE_2X
+	UCSR0A |= (1 << U2X0);	// enable double speed operation
+	//#else
+	//	UCSR0A &= ~(1 << U2X0);	// disable double speed operation
+	//#endif
+
+
+	// flush receive buffer
+	while ( UCSR0A & (1 << RXC0) ) UDR0;
+
+	// set 8N1
+	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
+	UCSR0B &= ~(1 << UCSZ02);
+
+	UCSR0B |= (1 << RXEN0)|(1 << TXEN0); //enable send and receive
+
+	UCSR0B |= (1 << RXCIE0); //enable receive interrup
+
+	rxhead0 = rxtail0 = rxbuf0;
+
+}
+
+
+
+void USART0_putc (char c)
+{
+
+	loop_until_bit_is_set(UCSR0A, UDRE0);
+	UDR0 = c;
+}
+
+
+uint8_t USART0_Getc_nb(uint8_t *c)
+{
+	if (rxhead0==rxtail0) return 0;
+	*c = *rxtail0;
+	if (++rxtail0 == (rxbuf0 + UART_RXBUFSIZE)) rxtail0 = rxbuf0;
+
+//	uint8_t diff = rxhead0 - rxtail0;
+//	if((diff < 10)&&(xon==1))
+//	{
+//		xon=0;
+//		//set the CTS pin
+//	}
+
+	return 1;
+}
+
+void USART0_crlf(){
+	USART0_putc(0x0A); //newline
+	USART0_putc(0x0D); //carriage return
+};
+
+void USART0_put_uint8(uint8_t x){
+	USART0_putc(((x & 0b11110000)>>4)+0x30);
+	USART0_putc((x & 0b00001111)+0x30);
+
+}
+void USART0_put_uint16(uint16_t x){
+	USART0_put_uint8 ((x & 0xFF00)>>8);
+	USART0_put_uint8 (x & 0x00FF);
+
+}
diff --git a/firmware/usart.h b/firmware/usart.h
new file mode 100644
index 0000000..d0ddebc
--- /dev/null
+++ b/firmware/usart.h
@@ -0,0 +1,34 @@
+/*
+ * PentaFnord Firmware
+ *
+ * by Alexander Lorz <bigalex@gmx.de>
+ *
+ *
+ * The USART control code is derived by code from the 4CHLED project
+ * by sebseb7: https://github.com/sebseb7/eagle/tree/master/4CHLED/firmware
+ *
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 3 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _USART_H
+#define _USART_H
+
+void USART0_Init (void);
+void USART0_putc (char c);
+uint8_t USART0_Getc_nb(uint8_t*);
+void USART0_put_uint8(uint8_t);
+void USART0_crlf();
+void USART0_put_uint16(uint16_t);
+
+#endif
+