diff --git a/sysmoOCTSIM/command.c b/sysmoOCTSIM/command.c
index b0949f3..6fa25cf 100644
--- a/sysmoOCTSIM/command.c
+++ b/sysmoOCTSIM/command.c
@@ -81,7 +81,7 @@
 	unsigned int i = 0;
 
 	/* yield CPU after maximum of 10 received characters */
-	while (usart_sync_is_rx_not_empty(&UART_debug) && (i < 10)) {
+	while (usart_async_is_rx_not_empty(&UART_debug) && (i < 10)) {
 		int c = getchar();
 		if (c < 0)
 			return;
diff --git a/sysmoOCTSIM/driver_init.c b/sysmoOCTSIM/driver_init.c
index 726129d..8a50925 100644
--- a/sysmoOCTSIM/driver_init.c
+++ b/sysmoOCTSIM/driver_init.c
@@ -32,6 +32,9 @@
 /*! The buffer size for USART */
 #define SIM6_BUFFER_SIZE 16
 
+/*! The buffer size for USART */
+#define UART_DEBUG_BUFFER_SIZE 32
+
 struct usart_async_descriptor SIM0;
 struct usart_async_descriptor SIM1;
 struct usart_async_descriptor SIM2;
@@ -48,7 +51,9 @@
 static uint8_t SIM5_buffer[SIM5_BUFFER_SIZE];
 static uint8_t SIM6_buffer[SIM6_BUFFER_SIZE];
 
-struct usart_sync_descriptor UART_debug;
+struct usart_async_descriptor UART_debug;
+
+static uint8_t UART_DEBUG_buffer[UART_DEBUG_BUFFER_SIZE];
 
 /**
  * \brief USART Clock initialization function
@@ -309,7 +314,26 @@
 	SIM6_PORT_init();
 }
 
-void UART_debug_PORT_init(void)
+/**
+ * \brief USART Clock initialization function
+ *
+ * Enables register interface and peripheral clock
+ */
+void UART_debug_CLOCK_init()
+{
+
+	hri_gclk_write_PCHCTRL_reg(GCLK, SERCOM7_GCLK_ID_CORE, CONF_GCLK_SERCOM7_CORE_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
+	hri_gclk_write_PCHCTRL_reg(GCLK, SERCOM7_GCLK_ID_SLOW, CONF_GCLK_SERCOM7_SLOW_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
+
+	hri_mclk_set_APBDMASK_SERCOM7_bit(MCLK);
+}
+
+/**
+ * \brief USART pinmux initialization function
+ *
+ * Set each required pin to USART functionality
+ */
+void UART_debug_PORT_init()
 {
 
 	gpio_set_pin_function(UART_TX, PINMUX_PB30C_SERCOM7_PAD0);
@@ -317,18 +341,15 @@
 	gpio_set_pin_function(UART_RX, PINMUX_PB31C_SERCOM7_PAD1);
 }
 
-void UART_debug_CLOCK_init(void)
-{
-	hri_gclk_write_PCHCTRL_reg(GCLK, SERCOM7_GCLK_ID_CORE, CONF_GCLK_SERCOM7_CORE_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
-	hri_gclk_write_PCHCTRL_reg(GCLK, SERCOM7_GCLK_ID_SLOW, CONF_GCLK_SERCOM7_SLOW_SRC | (1 << GCLK_PCHCTRL_CHEN_Pos));
-
-	hri_mclk_set_APBDMASK_SERCOM7_bit(MCLK);
-}
-
+/**
+ * \brief USART initialization function
+ *
+ * Enables USART peripheral, clocks and initializes USART driver
+ */
 void UART_debug_init(void)
 {
 	UART_debug_CLOCK_init();
-	usart_sync_init(&UART_debug, SERCOM7, (void *)NULL);
+	usart_async_init(&UART_debug, SERCOM7, UART_DEBUG_buffer, UART_DEBUG_BUFFER_SIZE, (void *)NULL);
 	UART_debug_PORT_init();
 }
 
diff --git a/sysmoOCTSIM/driver_init.h b/sysmoOCTSIM/driver_init.h
index d809db8..9d009b9 100644
--- a/sysmoOCTSIM/driver_init.h
+++ b/sysmoOCTSIM/driver_init.h
@@ -40,8 +40,7 @@
 extern struct usart_async_descriptor SIM4;
 extern struct usart_async_descriptor SIM5;
 extern struct usart_async_descriptor SIM6;
-
-extern struct usart_sync_descriptor UART_debug;
+extern struct usart_async_descriptor UART_debug;
 
 void SIM0_PORT_init(void);
 void SIM0_CLOCK_init(void);
diff --git a/sysmoOCTSIM/hpl/sercom/hpl_sercom.c b/sysmoOCTSIM/hpl/sercom/hpl_sercom.c
index b14e720..f235115 100644
--- a/sysmoOCTSIM/hpl/sercom/hpl_sercom.c
+++ b/sysmoOCTSIM/hpl/sercom/hpl_sercom.c
@@ -177,6 +177,8 @@
 
 static struct _usart_async_device *_sercom6_dev = NULL;
 
+static struct _usart_async_device *_sercom7_dev = NULL;
+
 static uint8_t _get_sercom_index(const void *const hw);
 static uint8_t _sercom_get_irq_num(const void *const hw);
 static void    _sercom_init_irq_param(const void *const hw, void *dev);
@@ -665,6 +667,10 @@
 	if (hw == SERCOM6) {
 		_sercom6_dev = (struct _usart_async_device *)dev;
 	}
+
+	if (hw == SERCOM7) {
+		_sercom7_dev = (struct _usart_async_device *)dev;
+	}
 }
 
 /**
@@ -2628,6 +2634,35 @@
 	_sercom_usart_interrupt_handler(_sercom6_dev);
 }
 
+/**
+ * \internal Sercom interrupt handler
+ */
+void SERCOM7_0_Handler(void)
+{
+	_sercom_usart_interrupt_handler(_sercom7_dev);
+}
+/**
+ * \internal Sercom interrupt handler
+ */
+void SERCOM7_1_Handler(void)
+{
+	_sercom_usart_interrupt_handler(_sercom7_dev);
+}
+/**
+ * \internal Sercom interrupt handler
+ */
+void SERCOM7_2_Handler(void)
+{
+	_sercom_usart_interrupt_handler(_sercom7_dev);
+}
+/**
+ * \internal Sercom interrupt handler
+ */
+void SERCOM7_3_Handler(void)
+{
+	_sercom_usart_interrupt_handler(_sercom7_dev);
+}
+
 int32_t _spi_m_sync_init(struct _spi_m_sync_dev *dev, void *const hw)
 {
 	const struct sercomspi_regs_cfg *regs = _spi_get_regs((uint32_t)hw);
diff --git a/sysmoOCTSIM/main.c b/sysmoOCTSIM/main.c
index 843652b..47d1cd1 100644
--- a/sysmoOCTSIM/main.c
+++ b/sysmoOCTSIM/main.c
@@ -308,8 +308,6 @@
 {
 	atmel_start_init();
 
-	usart_sync_enable(&UART_debug);
-
 	usb_start();
 
 	board_init();
diff --git a/sysmoOCTSIM/manual_test.c b/sysmoOCTSIM/manual_test.c
index 5cc9bca..526414a 100644
--- a/sysmoOCTSIM/manual_test.c
+++ b/sysmoOCTSIM/manual_test.c
@@ -203,7 +203,7 @@
 	int c;
 
 	do {
-	} while (!usart_sync_is_rx_not_empty(&UART_debug));
+	} while (!usart_async_is_rx_not_empty(&UART_debug));
 
 	c = getchar();
 	if (c < 0)
diff --git a/sysmoOCTSIM/stdio_start.c b/sysmoOCTSIM/stdio_start.c
index 7450a08..e2fb0c2 100644
--- a/sysmoOCTSIM/stdio_start.c
+++ b/sysmoOCTSIM/stdio_start.c
@@ -9,15 +9,13 @@
 #include "atmel_start.h"
 #include "stdio_start.h"
 
-void STDIO_REDIRECT_0_example(void)
+static void UART_debug_rx_cb(const struct usart_async_descriptor *const io_descr)
 {
-	/* Print welcome message */
-	printf("\r\nHello ATMEL World!\r\n");
 }
 
 void stdio_redirect_init(void)
 {
-
-	usart_sync_enable(&UART_debug);
+	usart_async_register_callback(&UART_debug, USART_ASYNC_RXC_CB, UART_debug_rx_cb); // if no callback function is registered receive won't work, even if the callback does nothing
+	usart_async_enable(&UART_debug);
 	stdio_io_init(&UART_debug.io);
 }