diff --git a/.gitignore b/.gitignore
index a40d44d5..7f80f700 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,4 +16,4 @@ tags
 *.b#*
 blackmagic_upgrade
 *.exe
-
+.DS_Store
diff --git a/libopencm3 b/libopencm3
index 16df5b57..a6405c6f 160000
--- a/libopencm3
+++ b/libopencm3
@@ -1 +1 @@
-Subproject commit 16df5b57b8f7d80e7344188ba1a8484930a32afe
+Subproject commit a6405c6f2a3383173ad5da40ea167e206d950ad1
diff --git a/src/main.c b/src/main.c
index de119536..fe520d8e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -45,6 +45,7 @@ main(int argc, char **argv)
 		volatile struct exception e;
 		TRY_CATCH(e, EXCEPTION_ALL) {
 			gdb_main();
+			uart_pop();
 		}
 		if (e.type) {
 			gdb_putpacketz("EFF");
diff --git a/src/platforms/jeff/platform.c b/src/platforms/jeff/platform.c
index 986c22a4..0873c9c8 100644
--- a/src/platforms/jeff/platform.c
+++ b/src/platforms/jeff/platform.c
@@ -52,7 +52,9 @@ void sys_tick_handler(void)
 	if(running_status)
 		gpio_toggle(LED_PORT, LED_IDLE_RUN);
 
-	time_ms += 10;
+	time_ms += 1;
+
+	uart_pop();
 }
 
 uint32_t platform_time_ms(void)
@@ -79,7 +81,7 @@ static uint32_t timing_init(void)
 	uint32_t cal = 0;
 
 	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB);
-	systick_set_reload(480000);	/* Interrupt us at 10 Hz */
+	systick_set_reload(48000);	/* Interrupt us at 10 Hz */
 	systick_interrupt_enable();
 
 	systick_counter_enable();
@@ -110,11 +112,12 @@ void platform_init(void)
 	gpio_config_output(SRST_PORT, SRST_PIN, GPIO_OUT_FLAG_DEFAULT_HIGH);
 	gpio_set(SRST_PORT, SRST_PIN);
 
+	/* setup uart led, disable by default*/
+	gpio_config_output(LED_PORT_UART, LED_UART, 0);//GPIO_OUT_FLAG_DEFAULT_HIGH);
+	gpio_clear(LED_PORT_UART, LED_UART);
+
 	timing_init();
-
-	//nvic_enable_irq(NVIC_UART0_IRQ);
-	//usbuart_init();
-
+	usbuart_init();
 	cdcacm_init();
 }
 
diff --git a/src/platforms/jeff/platform.h b/src/platforms/jeff/platform.h
index 8a8a7016..d205cb03 100644
--- a/src/platforms/jeff/platform.h
+++ b/src/platforms/jeff/platform.h
@@ -47,13 +47,13 @@ extern uint8_t running_status;
 #define TMS_PIN		GPIO7
 
 #define TCK_PORT	PORTA
-#define TCK_PIN		GPIO8
+#define TCK_PIN		GPIO5
 
 #define TDI_PORT	PORTA
-#define TDI_PIN		GPIO5
+#define TDI_PIN		GPIO3
 
 #define TDO_PORT	PORTA
-#define TDO_PIN		GPIO4
+#define TDO_PIN		GPIO2
 
 #define SWO_PORT	PORTA
 #define SWO_PIN		GPIO6
@@ -68,6 +68,9 @@ extern uint8_t running_status;
 #define SRST_PORT	PORTA
 #define SRST_PIN	GPIO6
 
+#define LED_PORT_UART	PORTA
+#define LED_UART	GPIO12
+
 #else
 
 #define LED_PORT	PORTA
@@ -98,6 +101,10 @@ extern uint8_t running_status;
 
 #define SRST_PORT	PORTA
 #define SRST_PIN	GPIO26
+
+#define LED_PORT_UART	PORTA
+#define LED_UART	GPIO12
+
 #endif
 
 #define TMS_SET_MODE()	{ \
@@ -123,25 +130,25 @@ extern uint8_t running_status;
 
 #define gpio_set_val(port, pin, val) do {	\
 	if(val)					\
-		gpio_set((port), (pin));	\
+		_gpio_set((port), (pin));	\
 	else					\
-		gpio_clear((port), (pin));	\
+		_gpio_clear((port), (pin));	\
 } while(0)
 
 #ifdef INLINE_GPIO
-static inline void _gpio_set(uint32_t gpioport, uint16_t gpios)
+static inline void _gpio_set(uint32_t gpioport, uint32_t gpios)
 {
 	PORT_OUTSET(gpioport) = gpios;
 }
 #define gpio_set _gpio_set
 
-static inline void _gpio_clear(uint32_t gpioport, uint16_t gpios)
+static inline void _gpio_clear(uint32_t gpioport, uint32_t gpios)
 {
 	PORT_OUTCLR(gpioport) = gpios;
 }
 #define gpio_clear _gpio_clear
 
-static inline uint16_t _gpio_get(uint32_t gpioport, uint16_t gpios)
+static inline uint16_t _gpio_get(uint32_t gpioport, uint32_t gpios)
 {
 	return (uint32_t)PORT_IN(gpioport) & gpios;
 }
@@ -158,4 +165,6 @@ static inline int platform_hwversion(void)
 {
 	        return 0;
 }
+
+void uart_pop(void);
 #endif
diff --git a/src/platforms/samd/jtagtap.c b/src/platforms/samd/jtagtap.c
index 056a4fdb..07d67aeb 100644
--- a/src/platforms/samd/jtagtap.c
+++ b/src/platforms/samd/jtagtap.c
@@ -40,4 +40,3 @@ jtagtap_next(const uint8_t dTMS, const uint8_t dTDI)
 
 	return ret != 0;
 }
-
diff --git a/src/platforms/samd/usbuart.c b/src/platforms/samd/usbuart.c
index ceaef1b7..b7bd078b 100644
--- a/src/platforms/samd/usbuart.c
+++ b/src/platforms/samd/usbuart.c
@@ -21,26 +21,105 @@
 #include "general.h"
 #include "cdcacm.h"
 
+#include <libopencm3/sam/d/bitfield.h>
+#include <libopencm3/sam/d/gclk.h>
+#include <libopencm3/sam/d/pm.h>
+#include <libopencm3/sam/d/port.h>
+#include <libopencm3/sam/d/nvic.h>
+#include <libopencm3/sam/d/uart.h>
+
+#include <libopencm3/cm3/cortex.h>
 #include <libopencm3/cm3/nvic.h>
+#include <libopencm3/cm3/scb.h>
 #include <libopencm3/cm3/scs.h>
+#include <libopencm3/cm3/systick.h>
+
 #include <libopencm3/usb/usbd.h>
 #include <libopencm3/usb/cdc.h>
 
+#include "queue.h"
+
+#define USART_NUM	0
+#define Q_SIZE		1024
+
+usbd_device * usbdev;
+
+/* input and output ring buffer */
+struct {
+        char buf[Q_SIZE];
+        volatile size_t head, tail;
+} rx, tx;
+
+/* non blocking putc function */
+static void usart_putc(char c)
+{
+#ifndef CONSOLE_NO_AUTO_CRLF
+	if (c == '\n')
+		usart_putc('\r');
+#endif
+
+	if (qfull(tx.head, tx.tail, Q_SIZE))
+		return;
+
+	cm_disable_interrupts();
+	tx.buf[tx.head] = c;
+	tx.head = qinc(tx.head, Q_SIZE);
+	cm_enable_interrupts();
+
+	/* kick the transmitter to restart interrupts */
+	usart_enable_tx_interrupt(USART_NUM);
+}
+
 void usbuart_init(void)
 {
+	/* enable gpios */
+	gpio_config_special(PORTA, GPIO8, SOC_GPIO_PERIPH_C); /* tx pin */
+	gpio_config_special(PORTA, GPIO9, SOC_GPIO_PERIPH_C); /* rx pin */
+
+	/* enable clocking to sercom3 */
+	set_periph_clk(GCLK0, GCLK_ID_SERCOM0_CORE);
+	periph_clk_en(GCLK_ID_SERCOM0_CORE, 1);
+
+	usart_enable(USART_NUM, 115200);
+	usart_enable_rx_interrupt(USART_NUM);
+	usart_enable_tx_interrupt(USART_NUM);
 }
 
 void usbuart_set_line_coding(struct usb_cdc_line_coding *coding)
 {
+	/* Not supported yet, only 115200 8bits/etc */
 	(void) coding;
 }
 
 void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
 {
-	(void) dev;
-	(void) ep;
+	(void)ep;
+
+	char buf[CDCACM_PACKET_SIZE];
+	int len = usbd_ep_read_packet(dev, CDCACM_UART_ENDPOINT,
+					buf, CDCACM_PACKET_SIZE);
+
+	gpio_set(LED_PORT_UART, LED_UART);
+	for(int i = 0; i < len; i++) {
+		usart_putc(buf[i]); 
+	}
+	gpio_clear(LED_PORT_UART, LED_UART);
 }
 
+/* run by our systick timer */
+void uart_pop(void)
+{
+	if (cdcacm_get_config() != 1) {
+		return;
+	}
+
+        if (!qempty(rx.head, rx.tail)) {
+		if (usbd_ep_write_packet(usbdev, 0x83, &rx.buf[rx.tail], 1) == 0) {
+			return;
+		}
+		rx.tail = qinc(rx.tail, Q_SIZE);
+	}
+}
 
 void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep)
 {
@@ -48,11 +127,38 @@ void usbuart_usb_in_cb(usbd_device *dev, uint8_t ep)
 	(void) ep;
 }
 
-/*
- * Read a character from the UART RX and stuff it in a software FIFO.
- * Allowed to read from FIFO out pointer, but not write to it.
- * Allowed to write to FIFO in pointer.
- */
-void USBUART_ISR(void)
+/************************** UART Interrupt Handlers *************************/
+static void uart_rx_irq(void)
 {
+	char c = UART(USART_NUM)->data;
+		
+	/* bug?, need to re-enable rx complete interrupt */
+	INSERTBF(UART_INTENSET_RXC, 1, UART(0)->intenset);
+
+	if (!qfull(rx.head, rx.tail, Q_SIZE)) {
+		rx.buf[rx.head] = c;
+		rx.head = qinc(rx.head, Q_SIZE);
+	}
+}
+
+static void uart_tx_irq(void)
+{
+	if (!qempty(tx.head, tx.tail)) {
+		usart_send(USART_NUM, tx.buf[tx.tail]);
+		tx.tail = qinc(tx.tail, Q_SIZE);
+	} else {
+		usart_disable_tx_interrupt(USART_NUM);
+	}
+}
+
+void sercom0_isr(void)
+{
+	/* Turn on LED */
+	gpio_set(LED_PORT_UART, LED_UART);
+
+	if (GETBF(UART_INTFLAG_RXC, UART(USART_NUM)->intflag))
+		uart_rx_irq();
+
+	if (GETBF(UART_INTFLAG_DRE, UART(USART_NUM)->intflag))
+		uart_tx_irq();
 }