diff --git a/Makefile b/Makefile
index 8c8967ea..160251c3 100644
--- a/Makefile
+++ b/Makefile
@@ -26,7 +26,7 @@ PYTHON=python
 
 # Source files
 src-y=sched.c command.c stepper.c basecmd.c gpiocmds.c spicmds.c endstop.c
-DIRS=src src/avr src/simulator
+DIRS=src src/avr src/simulator lib/pjrc_usb_serial
 
 # Default compiler flags
 cc-option=$(shell if test -z "`$(1) $(2) -S -o /dev/null -xc /dev/null 2>&1`" \
diff --git a/klippy/pins.py b/klippy/pins.py
index fad41643..d2d884d1 100644
--- a/klippy/pins.py
+++ b/klippy/pins.py
@@ -21,6 +21,7 @@ PINS_atmega1280 = avr_pins(12)
 
 MCU_PINS = {
     "atmega168": PINS_atmega164, "atmega644p": PINS_atmega164,
+    "at90usb1286": avr_pins(5),
     "atmega1280": PINS_atmega1280, "atmega2560": PINS_atmega1280,
 }
 
diff --git a/lib/README b/lib/README
new file mode 100644
index 00000000..ce9b6524
--- /dev/null
+++ b/lib/README
@@ -0,0 +1,6 @@
+This directory contains external library code.
+
+The pjrc_usb_serial directory contains code from:
+  http://www.pjrc.com/teensy/usb_serial.html
+it has been modified to compile on recent versions of gcc. See
+usb_serial.patch for the modifications.
diff --git a/lib/pjrc_usb_serial/usb_serial.c b/lib/pjrc_usb_serial/usb_serial.c
new file mode 100644
index 00000000..ac5bc8a2
--- /dev/null
+++ b/lib/pjrc_usb_serial/usb_serial.c
@@ -0,0 +1,939 @@
+/* USB Serial Example for Teensy USB Development Board
+ * http://www.pjrc.com/teensy/usb_serial.html
+ * Copyright (c) 2008,2010,2011 PJRC.COM, LLC
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Version 1.0: Initial Release
+// Version 1.1: support Teensy++
+// Version 1.2: fixed usb_serial_available
+// Version 1.3: added transmit bandwidth test
+// Version 1.4: added usb_serial_write
+// Version 1.5: add support for Teensy 2.0
+// Version 1.6: fix zero length packet bug
+// Version 1.7: fix usb_serial_set_control
+
+#include <string.h>
+#define USB_SERIAL_PRIVATE_INCLUDE
+#include "usb_serial.h"
+
+
+/**************************************************************************
+ *
+ *  Configurable Options
+ *
+ **************************************************************************/
+
+// You can change these to give your code its own name.  On Windows,
+// these are only used before an INF file (driver install) is loaded.
+#define STR_MANUFACTURER	L"Your Name"
+#define STR_PRODUCT		L"USB Serial"
+
+// All USB serial devices are supposed to have a serial number
+// (according to Microsoft).  On windows, a new COM port is created
+// for every unique serial/vendor/product number combination.  If
+// you program 2 identical boards with 2 different serial numbers
+// and they are assigned COM7 and COM8, each will always get the
+// same COM port number because Windows remembers serial numbers.
+//
+// On Mac OS-X, a device file is created automatically which
+// incorperates the serial number, eg, /dev/cu-usbmodem12341
+//
+// Linux by default ignores the serial number, and creates device
+// files named /dev/ttyACM0, /dev/ttyACM1... in the order connected.
+// Udev rules (in /etc/udev/rules.d) can define persistent device
+// names linked to this serial number, as well as permissions, owner
+// and group settings.
+#define STR_SERIAL_NUMBER	L"12345"
+
+// Mac OS-X and Linux automatically load the correct drivers.  On
+// Windows, even though the driver is supplied by Microsoft, an
+// INF file is needed to load the driver.  These numbers need to
+// match the INF file.
+#define VENDOR_ID		0x16C0
+#define PRODUCT_ID		0x047A
+
+// When you write data, it goes into a USB endpoint buffer, which
+// is transmitted to the PC when it becomes full, or after a timeout
+// with no more writes.  Even if you write in exactly packet-size
+// increments, this timeout is used to send a "zero length packet"
+// that tells the PC no more data is expected and it should pass
+// any buffered data to the application that may be waiting.  If
+// you want data sent immediately, call usb_serial_flush_output().
+#define TRANSMIT_FLUSH_TIMEOUT	5   /* in milliseconds */
+
+// If the PC is connected but not "listening", this is the length
+// of time before usb_serial_getchar() returns with an error.  This
+// is roughly equivilant to a real UART simply transmitting the
+// bits on a wire where nobody is listening, except you get an error
+// code which you can ignore for serial-like discard of data, or
+// use to know your data wasn't sent.
+#define TRANSMIT_TIMEOUT	25   /* in milliseconds */
+
+// USB devices are supposed to implment a halt feature, which is
+// rarely (if ever) used.  If you comment this line out, the halt
+// code will be removed, saving 116 bytes of space (gcc 4.3.0).
+// This is not strictly USB compliant, but works with all major
+// operating systems.
+#define SUPPORT_ENDPOINT_HALT
+
+
+
+/**************************************************************************
+ *
+ *  Endpoint Buffer Configuration
+ *
+ **************************************************************************/
+
+// These buffer sizes are best for most applications, but perhaps if you
+// want more buffering on some endpoint at the expense of others, this
+// is where you can make such changes.  The AT90USB162 has only 176 bytes
+// of DPRAM (USB buffers) and only endpoints 3 & 4 can double buffer.
+
+#define ENDPOINT0_SIZE		16
+#define CDC_ACM_ENDPOINT	2
+#define CDC_RX_ENDPOINT		3
+#define CDC_TX_ENDPOINT		4
+#if defined(__AVR_AT90USB162__)
+#define CDC_ACM_SIZE		16
+#define CDC_ACM_BUFFER		EP_SINGLE_BUFFER
+#define CDC_RX_SIZE		32
+#define CDC_RX_BUFFER 		EP_DOUBLE_BUFFER
+#define CDC_TX_SIZE		32
+#define CDC_TX_BUFFER		EP_DOUBLE_BUFFER
+#else
+#define CDC_ACM_SIZE		16
+#define CDC_ACM_BUFFER		EP_SINGLE_BUFFER
+#define CDC_RX_SIZE		64
+#define CDC_RX_BUFFER 		EP_DOUBLE_BUFFER
+#define CDC_TX_SIZE		64
+#define CDC_TX_BUFFER		EP_DOUBLE_BUFFER
+#endif
+
+static const uint8_t PROGMEM endpoint_config_table[] = {
+	0,
+	1, EP_TYPE_INTERRUPT_IN,  EP_SIZE(CDC_ACM_SIZE) | CDC_ACM_BUFFER,
+	1, EP_TYPE_BULK_OUT,      EP_SIZE(CDC_RX_SIZE) | CDC_RX_BUFFER,
+	1, EP_TYPE_BULK_IN,       EP_SIZE(CDC_TX_SIZE) | CDC_TX_BUFFER
+};
+
+
+/**************************************************************************
+ *
+ *  Descriptor Data
+ *
+ **************************************************************************/
+
+// Descriptors are the data that your computer reads when it auto-detects
+// this USB device (called "enumeration" in USB lingo).  The most commonly
+// changed items are editable at the top of this file.  Changing things
+// in here should only be done by those who've read chapter 9 of the USB
+// spec and relevant portions of any USB class specifications!
+
+static const uint8_t PROGMEM device_descriptor[] = {
+	18,					// bLength
+	1,					// bDescriptorType
+	0x00, 0x02,				// bcdUSB
+	2,					// bDeviceClass
+	0,					// bDeviceSubClass
+	0,					// bDeviceProtocol
+	ENDPOINT0_SIZE,				// bMaxPacketSize0
+	LSB(VENDOR_ID), MSB(VENDOR_ID),		// idVendor
+	LSB(PRODUCT_ID), MSB(PRODUCT_ID),	// idProduct
+	0x00, 0x01,				// bcdDevice
+	1,					// iManufacturer
+	2,					// iProduct
+	3,					// iSerialNumber
+	1					// bNumConfigurations
+};
+
+#define CONFIG1_DESC_SIZE (9+9+5+5+4+5+7+9+7+7)
+static const uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
+	// configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
+	9, 					// bLength;
+	2,					// bDescriptorType;
+	LSB(CONFIG1_DESC_SIZE),			// wTotalLength
+	MSB(CONFIG1_DESC_SIZE),
+	2,					// bNumInterfaces
+	1,					// bConfigurationValue
+	0,					// iConfiguration
+	0xC0,					// bmAttributes
+	50,					// bMaxPower
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	0,					// bInterfaceNumber
+	0,					// bAlternateSetting
+	1,					// bNumEndpoints
+	0x02,					// bInterfaceClass
+	0x02,					// bInterfaceSubClass
+	0x01,					// bInterfaceProtocol
+	0,					// iInterface
+	// CDC Header Functional Descriptor, CDC Spec 5.2.3.1, Table 26
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x00,					// bDescriptorSubtype
+	0x10, 0x01,				// bcdCDC
+	// Call Management Functional Descriptor, CDC Spec 5.2.3.2, Table 27
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x01,					// bDescriptorSubtype
+	0x01,					// bmCapabilities
+	1,					// bDataInterface
+	// Abstract Control Management Functional Descriptor, CDC Spec 5.2.3.3, Table 28
+	4,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x02,					// bDescriptorSubtype
+	0x06,					// bmCapabilities
+	// Union Functional Descriptor, CDC Spec 5.2.3.8, Table 33
+	5,					// bFunctionLength
+	0x24,					// bDescriptorType
+	0x06,					// bDescriptorSubtype
+	0,					// bMasterInterface
+	1,					// bSlaveInterface0
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_ACM_ENDPOINT | 0x80,		// bEndpointAddress
+	0x03,					// bmAttributes (0x03=intr)
+	CDC_ACM_SIZE, 0,			// wMaxPacketSize
+	64,					// bInterval
+	// interface descriptor, USB spec 9.6.5, page 267-269, Table 9-12
+	9,					// bLength
+	4,					// bDescriptorType
+	1,					// bInterfaceNumber
+	0,					// bAlternateSetting
+	2,					// bNumEndpoints
+	0x0A,					// bInterfaceClass
+	0x00,					// bInterfaceSubClass
+	0x00,					// bInterfaceProtocol
+	0,					// iInterface
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_RX_ENDPOINT,			// bEndpointAddress
+	0x02,					// bmAttributes (0x02=bulk)
+	CDC_RX_SIZE, 0,				// wMaxPacketSize
+	0,					// bInterval
+	// endpoint descriptor, USB spec 9.6.6, page 269-271, Table 9-13
+	7,					// bLength
+	5,					// bDescriptorType
+	CDC_TX_ENDPOINT | 0x80,			// bEndpointAddress
+	0x02,					// bmAttributes (0x02=bulk)
+	CDC_TX_SIZE, 0,				// wMaxPacketSize
+	0					// bInterval
+};
+
+// If you're desperate for a little extra code memory, these strings
+// can be completely removed if iManufacturer, iProduct, iSerialNumber
+// in the device desciptor are changed to zeros.
+struct usb_string_descriptor_struct {
+	uint8_t bLength;
+	uint8_t bDescriptorType;
+	int16_t wString[];
+};
+static const struct usb_string_descriptor_struct PROGMEM string0 = {
+	4,
+	3,
+	{0x0409}
+};
+static const struct usb_string_descriptor_struct PROGMEM string1 = {
+	sizeof(STR_MANUFACTURER),
+	3,
+	STR_MANUFACTURER
+};
+static const struct usb_string_descriptor_struct PROGMEM string2 = {
+	sizeof(STR_PRODUCT),
+	3,
+	STR_PRODUCT
+};
+static const struct usb_string_descriptor_struct PROGMEM string3 = {
+	sizeof(STR_SERIAL_NUMBER),
+	3,
+	STR_SERIAL_NUMBER
+};
+
+// This table defines which descriptor data is sent for each specific
+// request from the host (in wValue and wIndex).
+static const struct descriptor_list_struct {
+	uint16_t	wValue;
+	uint16_t	wIndex;
+	const uint8_t	*addr;
+	uint8_t		length;
+} PROGMEM descriptor_list[] = {
+	{0x0100, 0x0000, device_descriptor, sizeof(device_descriptor)},
+	{0x0200, 0x0000, config1_descriptor, sizeof(config1_descriptor)},
+	{0x0300, 0x0000, (const uint8_t *)&string0, 4},
+	{0x0301, 0x0409, (const uint8_t *)&string1, sizeof(STR_MANUFACTURER)},
+	{0x0302, 0x0409, (const uint8_t *)&string2, sizeof(STR_PRODUCT)},
+	{0x0303, 0x0409, (const uint8_t *)&string3, sizeof(STR_SERIAL_NUMBER)}
+};
+#define NUM_DESC_LIST (sizeof(descriptor_list)/sizeof(struct descriptor_list_struct))
+
+
+/**************************************************************************
+ *
+ *  Variables - these are the only non-stack RAM usage
+ *
+ **************************************************************************/
+
+// zero when we are not configured, non-zero when enumerated
+static volatile uint8_t usb_configuration=0;
+
+// the time remaining before we transmit any partially full
+// packet, or send a zero length packet.
+static volatile uint8_t transmit_flush_timer=0;
+static uint8_t transmit_previous_timeout=0;
+
+// serial port settings (baud rate, control signals, etc) set
+// by the PC.  These are ignored, but kept in RAM.
+static uint8_t cdc_line_coding[7]={0x00, 0xE1, 0x00, 0x00, 0x00, 0x00, 0x08};
+static uint8_t cdc_line_rtsdtr=0;
+
+
+/**************************************************************************
+ *
+ *  Public Functions - these are the API intended for the user
+ *
+ **************************************************************************/
+
+// initialize USB serial
+void usb_init(void)
+{
+	HW_CONFIG();
+        USB_FREEZE();				// enable USB
+        PLL_CONFIG();				// config PLL, 16 MHz xtal
+        while (!(PLLCSR & (1<<PLOCK))) ;	// wait for PLL lock
+        USB_CONFIG();				// start USB clock
+        UDCON = 0;				// enable attach resistor
+	usb_configuration = 0;
+	cdc_line_rtsdtr = 0;
+        UDIEN = (1<<EORSTE)|(1<<SOFE);
+	sei();
+}
+
+// return 0 if the USB is not configured, or the configuration
+// number selected by the HOST
+uint8_t usb_configured(void)
+{
+	return usb_configuration;
+}
+
+// get the next character, or -1 if nothing received
+int16_t usb_serial_getchar(void)
+{
+	uint8_t c, intr_state;
+
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	if (!usb_configuration) {
+		SREG = intr_state;
+		return -1;
+	}
+	UENUM = CDC_RX_ENDPOINT;
+	retry:
+	c = UEINTX;
+	if (!(c & (1<<RWAL))) {
+		// no data in buffer
+		if (c & (1<<RXOUTI)) {
+			UEINTX = 0x6B;
+			goto retry;
+		}	
+		SREG = intr_state;
+		return -1;
+	}
+	// take one byte out of the buffer
+	c = UEDATX;
+	// if buffer completely used, release it
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x6B;
+	SREG = intr_state;
+	return c;
+}
+
+// number of bytes available in the receive buffer
+uint8_t usb_serial_available(void)
+{
+	uint8_t n=0, i, intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (usb_configuration) {
+		UENUM = CDC_RX_ENDPOINT;
+		n = UEBCLX;
+		if (!n) {
+			i = UEINTX;
+			if (i & (1<<RXOUTI) && !(i & (1<<RWAL))) UEINTX = 0x6B;
+		}
+	}
+	SREG = intr_state;
+	return n;
+}
+
+// discard any buffered input
+void usb_serial_flush_input(void)
+{
+	uint8_t intr_state;
+
+	if (usb_configuration) {
+		intr_state = SREG;
+		cli();
+		UENUM = CDC_RX_ENDPOINT;
+		while ((UEINTX & (1<<RWAL))) {
+			UEINTX = 0x6B; 
+		}
+		SREG = intr_state;
+	}
+}
+
+// transmit a character.  0 returned on success, -1 on error
+int8_t usb_serial_putchar(uint8_t c)
+{
+	uint8_t timeout, intr_state;
+
+	// if we're not online (enumerated and configured), error
+	if (!usb_configuration) return -1;
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	// if we gave up due to timeout before, don't wait again
+	if (transmit_previous_timeout) {
+		if (!(UEINTX & (1<<RWAL))) {
+			SREG = intr_state;
+			return -1;
+		}
+		transmit_previous_timeout = 0;
+	}
+	// wait for the FIFO to be ready to accept data
+	timeout = UDFNUML + TRANSMIT_TIMEOUT;
+	while (1) {
+		// are we ready to transmit?
+		if (UEINTX & (1<<RWAL)) break;
+		SREG = intr_state;
+		// have we waited too long?  This happens if the user
+		// is not running an application that is listening
+		if (UDFNUML == timeout) {
+			transmit_previous_timeout = 1;
+			return -1;
+		}
+		// has the USB gone offline?
+		if (!usb_configuration) return -1;
+		// get ready to try checking again
+		intr_state = SREG;
+		cli();
+		UENUM = CDC_TX_ENDPOINT;
+	}
+	// actually write the byte into the FIFO
+	UEDATX = c;
+	// if this completed a packet, transmit it now!
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+	transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+	SREG = intr_state;
+	return 0;
+}
+
+
+// transmit a character, but do not wait if the buffer is full,
+//   0 returned on success, -1 on buffer full or error 
+int8_t usb_serial_putchar_nowait(uint8_t c)
+{
+	uint8_t intr_state;
+
+	if (!usb_configuration) return -1;
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	if (!(UEINTX & (1<<RWAL))) {
+		// buffer is full
+		SREG = intr_state;
+		return -1;
+	}
+	// actually write the byte into the FIFO
+	UEDATX = c;
+		// if this completed a packet, transmit it now!
+	if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+	transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+	SREG = intr_state;
+	return 0;
+}
+
+// transmit a buffer.
+//  0 returned on success, -1 on error
+// This function is optimized for speed!  Each call takes approx 6.1 us overhead
+// plus 0.25 us per byte.  12 Mbit/sec USB has 8.67 us per-packet overhead and
+// takes 0.67 us per byte.  If called with 64 byte packet-size blocks, this function
+// can transmit at full USB speed using 43% CPU time.  The maximum theoretical speed
+// is 19 packets per USB frame, or 1216 kbytes/sec.  However, bulk endpoints have the
+// lowest priority, so any other USB devices will likely reduce the speed.  Speed
+// can also be limited by how quickly the PC-based software reads data, as the host
+// controller in the PC will not allocate bandwitdh without a pending read request.
+// (thanks to Victor Suarez for testing and feedback and initial code)
+
+int8_t usb_serial_write(const uint8_t *buffer, uint16_t size)
+{
+	uint8_t timeout, intr_state, write_size;
+
+	// if we're not online (enumerated and configured), error
+	if (!usb_configuration) return -1;
+	// interrupts are disabled so these functions can be
+	// used from the main program or interrupt context,
+	// even both in the same program!
+	intr_state = SREG;
+	cli();
+	UENUM = CDC_TX_ENDPOINT;
+	// if we gave up due to timeout before, don't wait again
+	if (transmit_previous_timeout) {
+		if (!(UEINTX & (1<<RWAL))) {
+			SREG = intr_state;
+			return -1;
+		}
+		transmit_previous_timeout = 0;
+	}
+	// each iteration of this loop transmits a packet
+	while (size) {
+		// wait for the FIFO to be ready to accept data
+		timeout = UDFNUML + TRANSMIT_TIMEOUT;
+		while (1) {
+			// are we ready to transmit?
+			if (UEINTX & (1<<RWAL)) break;
+			SREG = intr_state;
+			// have we waited too long?  This happens if the user
+			// is not running an application that is listening
+			if (UDFNUML == timeout) {
+				transmit_previous_timeout = 1;
+				return -1;
+			}
+			// has the USB gone offline?
+			if (!usb_configuration) return -1;
+			// get ready to try checking again
+			intr_state = SREG;
+			cli();
+			UENUM = CDC_TX_ENDPOINT;
+		}
+
+		// compute how many bytes will fit into the next packet
+		write_size = CDC_TX_SIZE - UEBCLX;
+		if (write_size > size) write_size = size;
+		size -= write_size;
+
+		// write the packet
+		switch (write_size) {
+			#if (CDC_TX_SIZE == 64)
+			case 64: UEDATX = *buffer++;
+			case 63: UEDATX = *buffer++;
+			case 62: UEDATX = *buffer++;
+			case 61: UEDATX = *buffer++;
+			case 60: UEDATX = *buffer++;
+			case 59: UEDATX = *buffer++;
+			case 58: UEDATX = *buffer++;
+			case 57: UEDATX = *buffer++;
+			case 56: UEDATX = *buffer++;
+			case 55: UEDATX = *buffer++;
+			case 54: UEDATX = *buffer++;
+			case 53: UEDATX = *buffer++;
+			case 52: UEDATX = *buffer++;
+			case 51: UEDATX = *buffer++;
+			case 50: UEDATX = *buffer++;
+			case 49: UEDATX = *buffer++;
+			case 48: UEDATX = *buffer++;
+			case 47: UEDATX = *buffer++;
+			case 46: UEDATX = *buffer++;
+			case 45: UEDATX = *buffer++;
+			case 44: UEDATX = *buffer++;
+			case 43: UEDATX = *buffer++;
+			case 42: UEDATX = *buffer++;
+			case 41: UEDATX = *buffer++;
+			case 40: UEDATX = *buffer++;
+			case 39: UEDATX = *buffer++;
+			case 38: UEDATX = *buffer++;
+			case 37: UEDATX = *buffer++;
+			case 36: UEDATX = *buffer++;
+			case 35: UEDATX = *buffer++;
+			case 34: UEDATX = *buffer++;
+			case 33: UEDATX = *buffer++;
+			#endif
+			#if (CDC_TX_SIZE >= 32)
+			case 32: UEDATX = *buffer++;
+			case 31: UEDATX = *buffer++;
+			case 30: UEDATX = *buffer++;
+			case 29: UEDATX = *buffer++;
+			case 28: UEDATX = *buffer++;
+			case 27: UEDATX = *buffer++;
+			case 26: UEDATX = *buffer++;
+			case 25: UEDATX = *buffer++;
+			case 24: UEDATX = *buffer++;
+			case 23: UEDATX = *buffer++;
+			case 22: UEDATX = *buffer++;
+			case 21: UEDATX = *buffer++;
+			case 20: UEDATX = *buffer++;
+			case 19: UEDATX = *buffer++;
+			case 18: UEDATX = *buffer++;
+			case 17: UEDATX = *buffer++;
+			#endif
+			#if (CDC_TX_SIZE >= 16)
+			case 16: UEDATX = *buffer++;
+			case 15: UEDATX = *buffer++;
+			case 14: UEDATX = *buffer++;
+			case 13: UEDATX = *buffer++;
+			case 12: UEDATX = *buffer++;
+			case 11: UEDATX = *buffer++;
+			case 10: UEDATX = *buffer++;
+			case  9: UEDATX = *buffer++;
+			#endif
+			case  8: UEDATX = *buffer++;
+			case  7: UEDATX = *buffer++;
+			case  6: UEDATX = *buffer++;
+			case  5: UEDATX = *buffer++;
+			case  4: UEDATX = *buffer++;
+			case  3: UEDATX = *buffer++;
+			case  2: UEDATX = *buffer++;
+			default:
+			case  1: UEDATX = *buffer++;
+			case  0: break;
+		}
+		// if this completed a packet, transmit it now!
+		if (!(UEINTX & (1<<RWAL))) UEINTX = 0x3A;
+		transmit_flush_timer = TRANSMIT_FLUSH_TIMEOUT;
+		SREG = intr_state;
+	}
+	return 0;
+}
+
+
+// immediately transmit any buffered output.
+// This doesn't actually transmit the data - that is impossible!
+// USB devices only transmit when the host allows, so the best
+// we can do is release the FIFO buffer for when the host wants it
+void usb_serial_flush_output(void)
+{
+	uint8_t intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (transmit_flush_timer) {
+		UENUM = CDC_TX_ENDPOINT;
+		UEINTX = 0x3A;
+		transmit_flush_timer = 0;
+	}
+	SREG = intr_state;
+}
+
+// functions to read the various async serial settings.  These
+// aren't actually used by USB at all (communication is always
+// at full USB speed), but they are set by the host so we can
+// set them properly if we're converting the USB to a real serial
+// communication
+uint32_t usb_serial_get_baud(void)
+{
+	uint32_t res;
+	memcpy(&res, cdc_line_coding, sizeof(res));
+	return res;
+}
+uint8_t usb_serial_get_stopbits(void)
+{
+	return cdc_line_coding[4];
+}
+uint8_t usb_serial_get_paritytype(void)
+{
+	return cdc_line_coding[5];
+}
+uint8_t usb_serial_get_numbits(void)
+{
+	return cdc_line_coding[6];
+}
+uint8_t usb_serial_get_control(void)
+{
+	return cdc_line_rtsdtr;
+}
+// write the control signals, DCD, DSR, RI, etc
+// There is no CTS signal.  If software on the host has transmitted
+// data to you but you haven't been calling the getchar function,
+// it remains buffered (either here or on the host) and can not be
+// lost because you weren't listening at the right time, like it
+// would in real serial communication.
+int8_t usb_serial_set_control(uint8_t signals)
+{
+	uint8_t intr_state;
+
+	intr_state = SREG;
+	cli();
+	if (!usb_configuration) {
+		// we're not enumerated/configured
+		SREG = intr_state;
+		return -1;
+	}
+
+	UENUM = CDC_ACM_ENDPOINT;
+	if (!(UEINTX & (1<<RWAL))) {
+		// unable to write
+		// TODO; should this try to abort the previously
+		// buffered message??
+		SREG = intr_state;
+		return -1;
+	}
+	UEDATX = 0xA1;
+	UEDATX = 0x20;
+	UEDATX = 0;
+	UEDATX = 0;
+	UEDATX = 0; // 0 seems to work nicely.  what if this is 1??
+	UEDATX = 0;
+	UEDATX = 1;
+	UEDATX = 0;
+	UEDATX = signals;
+	UEINTX = 0x3A;
+	SREG = intr_state;
+	return 0;
+}
+
+
+
+/**************************************************************************
+ *
+ *  Private Functions - not intended for general user consumption....
+ *
+ **************************************************************************/
+
+
+// USB Device Interrupt - handle all device-level events
+// the transmit buffer flushing is triggered by the start of frame
+//
+ISR(USB_GEN_vect)
+{
+	uint8_t intbits, t;
+
+        intbits = UDINT;
+        UDINT = 0;
+        if (intbits & (1<<EORSTI)) {
+		UENUM = 0;
+		UECONX = 1;
+		UECFG0X = EP_TYPE_CONTROL;
+		UECFG1X = EP_SIZE(ENDPOINT0_SIZE) | EP_SINGLE_BUFFER;
+		UEIENX = (1<<RXSTPE);
+		usb_configuration = 0;
+		cdc_line_rtsdtr = 0;
+        }
+	if (intbits & (1<<SOFI)) {
+		if (usb_configuration) {
+			t = transmit_flush_timer;
+			if (t) {
+				transmit_flush_timer = --t;
+				if (!t) {
+					UENUM = CDC_TX_ENDPOINT;
+					UEINTX = 0x3A;
+				}
+			}
+		}
+	}
+}
+
+
+// Misc functions to wait for ready and send/receive packets
+static inline void usb_wait_in_ready(void)
+{
+	while (!(UEINTX & (1<<TXINI))) ;
+}
+static inline void usb_send_in(void)
+{
+	UEINTX = ~(1<<TXINI);
+}
+static inline void usb_wait_receive_out(void)
+{
+	while (!(UEINTX & (1<<RXOUTI))) ;
+}
+static inline void usb_ack_out(void)
+{
+	UEINTX = ~(1<<RXOUTI);
+}
+
+
+
+// USB Endpoint Interrupt - endpoint 0 is handled here.  The
+// other endpoints are manipulated by the user-callable
+// functions, and the start-of-frame interrupt.
+//
+ISR(USB_COM_vect)
+{
+        uint8_t intbits;
+	const uint8_t *list;
+        const uint8_t *cfg;
+	uint8_t i, n, len, en;
+	uint8_t *p;
+	uint8_t bmRequestType;
+	uint8_t bRequest;
+	uint16_t wValue;
+	uint16_t wIndex;
+	uint16_t wLength;
+	uint16_t desc_val;
+	const uint8_t *desc_addr;
+	uint8_t	desc_length;
+
+        UENUM = 0;
+        intbits = UEINTX;
+        if (intbits & (1<<RXSTPI)) {
+                bmRequestType = UEDATX;
+                bRequest = UEDATX;
+                wValue = UEDATX;
+                wValue |= (UEDATX << 8);
+                wIndex = UEDATX;
+                wIndex |= (UEDATX << 8);
+                wLength = UEDATX;
+                wLength |= (UEDATX << 8);
+                UEINTX = ~((1<<RXSTPI) | (1<<RXOUTI) | (1<<TXINI));
+                if (bRequest == GET_DESCRIPTOR) {
+			list = (const uint8_t *)descriptor_list;
+			for (i=0; ; i++) {
+				if (i >= NUM_DESC_LIST) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);  //stall
+					return;
+				}
+				desc_val = pgm_read_word(list);
+				if (desc_val != wValue) {
+					list += sizeof(struct descriptor_list_struct);
+					continue;
+				}
+				list += 2;
+				desc_val = pgm_read_word(list);
+				if (desc_val != wIndex) {
+					list += sizeof(struct descriptor_list_struct)-2;
+					continue;
+				}
+				list += 2;
+				desc_addr = (const uint8_t *)pgm_read_word(list);
+				list += 2;
+				desc_length = pgm_read_byte(list);
+				break;
+			}
+			len = (wLength < 256) ? wLength : 255;
+			if (len > desc_length) len = desc_length;
+			do {
+				// wait for host ready for IN packet
+				do {
+					i = UEINTX;
+				} while (!(i & ((1<<TXINI)|(1<<RXOUTI))));
+				if (i & (1<<RXOUTI)) return;	// abort
+				// send IN packet
+				n = len < ENDPOINT0_SIZE ? len : ENDPOINT0_SIZE;
+				for (i = n; i; i--) {
+					UEDATX = pgm_read_byte(desc_addr++);
+				}
+				len -= n;
+				usb_send_in();
+			} while (len || n == ENDPOINT0_SIZE);
+			return;
+                }
+		if (bRequest == SET_ADDRESS) {
+			usb_send_in();
+			usb_wait_in_ready();
+			UDADDR = wValue | (1<<ADDEN);
+			return;
+		}
+		if (bRequest == SET_CONFIGURATION && bmRequestType == 0) {
+			usb_configuration = wValue;
+			cdc_line_rtsdtr = 0;
+			transmit_flush_timer = 0;
+			usb_send_in();
+			cfg = endpoint_config_table;
+			for (i=1; i<5; i++) {
+				UENUM = i;
+				en = pgm_read_byte(cfg++);
+				UECONX = en;
+				if (en) {
+					UECFG0X = pgm_read_byte(cfg++);
+					UECFG1X = pgm_read_byte(cfg++);
+				}
+			}
+        		UERST = 0x1E;
+        		UERST = 0;
+			return;
+		}
+		if (bRequest == GET_CONFIGURATION && bmRequestType == 0x80) {
+			usb_wait_in_ready();
+			UEDATX = usb_configuration;
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_GET_LINE_CODING && bmRequestType == 0xA1) {
+			usb_wait_in_ready();
+			p = cdc_line_coding;
+			for (i=0; i<7; i++) {
+				UEDATX = *p++;
+			}
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_SET_LINE_CODING && bmRequestType == 0x21) {
+			usb_wait_receive_out();
+			p = cdc_line_coding;
+			for (i=0; i<7; i++) {
+				*p++ = UEDATX;
+			}
+			usb_ack_out();
+			usb_send_in();
+			return;
+		}
+		if (bRequest == CDC_SET_CONTROL_LINE_STATE && bmRequestType == 0x21) {
+			cdc_line_rtsdtr = wValue;
+			usb_wait_in_ready();
+			usb_send_in();
+			return;
+		}
+		if (bRequest == GET_STATUS) {
+			usb_wait_in_ready();
+			i = 0;
+			#ifdef SUPPORT_ENDPOINT_HALT
+			if (bmRequestType == 0x82) {
+				UENUM = wIndex;
+				if (UECONX & (1<<STALLRQ)) i = 1;
+				UENUM = 0;
+			}
+			#endif
+			UEDATX = i;
+			UEDATX = 0;
+			usb_send_in();
+			return;
+		}
+		#ifdef SUPPORT_ENDPOINT_HALT
+		if ((bRequest == CLEAR_FEATURE || bRequest == SET_FEATURE)
+		  && bmRequestType == 0x02 && wValue == 0) {
+			i = wIndex & 0x7F;
+			if (i >= 1 && i <= MAX_ENDPOINT) {
+				usb_send_in();
+				UENUM = i;
+				if (bRequest == SET_FEATURE) {
+					UECONX = (1<<STALLRQ)|(1<<EPEN);
+				} else {
+					UECONX = (1<<STALLRQC)|(1<<RSTDT)|(1<<EPEN);
+					UERST = (1 << i);
+					UERST = 0;
+				}
+				return;
+			}
+		}
+		#endif
+        }
+	UECONX = (1<<STALLRQ) | (1<<EPEN);	// stall
+}
+
+
diff --git a/lib/pjrc_usb_serial/usb_serial.h b/lib/pjrc_usb_serial/usb_serial.h
new file mode 100644
index 00000000..14c5b1a7
--- /dev/null
+++ b/lib/pjrc_usb_serial/usb_serial.h
@@ -0,0 +1,124 @@
+#ifndef usb_serial_h__
+#define usb_serial_h__
+
+#include <stdint.h>
+
+// setup
+void usb_init(void);			// initialize everything
+uint8_t usb_configured(void);		// is the USB port configured
+
+// receiving data
+int16_t usb_serial_getchar(void);	// receive a character (-1 if timeout/error)
+uint8_t usb_serial_available(void);	// number of bytes in receive buffer
+void usb_serial_flush_input(void);	// discard any buffered input
+
+// transmitting data
+int8_t usb_serial_putchar(uint8_t c);	// transmit a character
+int8_t usb_serial_putchar_nowait(uint8_t c);  // transmit a character, do not wait
+int8_t usb_serial_write(const uint8_t *buffer, uint16_t size); // transmit a buffer
+void usb_serial_flush_output(void);	// immediately transmit any buffered output
+
+// serial parameters
+uint32_t usb_serial_get_baud(void);	// get the baud rate
+uint8_t usb_serial_get_stopbits(void);	// get the number of stop bits
+uint8_t usb_serial_get_paritytype(void);// get the parity type
+uint8_t usb_serial_get_numbits(void);	// get the number of data bits
+uint8_t usb_serial_get_control(void);	// get the RTS and DTR signal state
+int8_t usb_serial_set_control(uint8_t signals); // set DSR, DCD, RI, etc
+
+// constants corresponding to the various serial parameters
+#define USB_SERIAL_DTR			0x01
+#define USB_SERIAL_RTS			0x02
+#define USB_SERIAL_1_STOP		0
+#define USB_SERIAL_1_5_STOP		1
+#define USB_SERIAL_2_STOP		2
+#define USB_SERIAL_PARITY_NONE		0
+#define USB_SERIAL_PARITY_ODD		1
+#define USB_SERIAL_PARITY_EVEN		2
+#define USB_SERIAL_PARITY_MARK		3
+#define USB_SERIAL_PARITY_SPACE		4
+#define USB_SERIAL_DCD			0x01
+#define USB_SERIAL_DSR			0x02
+#define USB_SERIAL_BREAK		0x04
+#define USB_SERIAL_RI			0x08
+#define USB_SERIAL_FRAME_ERR		0x10
+#define USB_SERIAL_PARITY_ERR		0x20
+#define USB_SERIAL_OVERRUN_ERR		0x40
+
+// This file does not include the HID debug functions, so these empty
+// macros replace them with nothing, so users can compile code that
+// has calls to these functions.
+#define usb_debug_putchar(c)
+#define usb_debug_flush_output()
+
+
+
+// Everything below this point is only intended for usb_serial.c
+#ifdef USB_SERIAL_PRIVATE_INCLUDE
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/interrupt.h>
+
+#define EP_TYPE_CONTROL			0x00
+#define EP_TYPE_BULK_IN			0x81
+#define EP_TYPE_BULK_OUT		0x80
+#define EP_TYPE_INTERRUPT_IN		0xC1
+#define EP_TYPE_INTERRUPT_OUT		0xC0
+#define EP_TYPE_ISOCHRONOUS_IN		0x41
+#define EP_TYPE_ISOCHRONOUS_OUT		0x40
+#define EP_SINGLE_BUFFER		0x02
+#define EP_DOUBLE_BUFFER		0x06
+#define EP_SIZE(s)	((s) == 64 ? 0x30 :	\
+			((s) == 32 ? 0x20 :	\
+			((s) == 16 ? 0x10 :	\
+			             0x00)))
+
+#define MAX_ENDPOINT		4
+
+#define LSB(n) (n & 255)
+#define MSB(n) ((n >> 8) & 255)
+
+#if defined(__AVR_AT90USB162__)
+#define HW_CONFIG() 
+#define PLL_CONFIG() (PLLCSR = ((1<<PLLE)|(1<<PLLP0)))
+#define USB_CONFIG() (USBCON = (1<<USBE))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_ATmega32U4__)
+#define HW_CONFIG() (UHWCON = 0x01)
+#define PLL_CONFIG() (PLLCSR = 0x12)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB646__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x1A)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#elif defined(__AVR_AT90USB1286__)
+#define HW_CONFIG() (UHWCON = 0x81)
+#define PLL_CONFIG() (PLLCSR = 0x16)
+#define USB_CONFIG() (USBCON = ((1<<USBE)|(1<<OTGPADE)))
+#define USB_FREEZE() (USBCON = ((1<<USBE)|(1<<FRZCLK)))
+#endif
+
+// standard control endpoint request types
+#define GET_STATUS			0
+#define CLEAR_FEATURE			1
+#define SET_FEATURE			3
+#define SET_ADDRESS			5
+#define GET_DESCRIPTOR			6
+#define GET_CONFIGURATION		8
+#define SET_CONFIGURATION		9
+#define GET_INTERFACE			10
+#define SET_INTERFACE			11
+// HID (human interface device)
+#define HID_GET_REPORT			1
+#define HID_GET_PROTOCOL		3
+#define HID_SET_REPORT			9
+#define HID_SET_IDLE			10
+#define HID_SET_PROTOCOL		11
+// CDC (communication class device)
+#define CDC_SET_LINE_CODING		0x20
+#define CDC_GET_LINE_CODING		0x21
+#define CDC_SET_CONTROL_LINE_STATE	0x22
+#endif
+#endif
diff --git a/lib/pjrc_usb_serial/usb_serial.patch b/lib/pjrc_usb_serial/usb_serial.patch
new file mode 100644
index 00000000..5aaa08e8
--- /dev/null
+++ b/lib/pjrc_usb_serial/usb_serial.patch
@@ -0,0 +1,75 @@
+--- usb_serial.c	2011-04-19 05:54:12.000000000 -0400
++++ usb_serial.c	2016-06-04 23:48:52.590001697 -0400
+@@ -30,6 +30,7 @@
+ // Version 1.6: fix zero length packet bug
+ // Version 1.7: fix usb_serial_set_control
+ 
++#include <string.h>
+ #define USB_SERIAL_PRIVATE_INCLUDE
+ #include "usb_serial.h"
+ 
+@@ -146,7 +147,7 @@
+ // in here should only be done by those who've read chapter 9 of the USB
+ // spec and relevant portions of any USB class specifications!
+ 
+-static uint8_t PROGMEM device_descriptor[] = {
++static const uint8_t PROGMEM device_descriptor[] = {
+ 	18,					// bLength
+ 	1,					// bDescriptorType
+ 	0x00, 0x02,				// bcdUSB
+@@ -164,7 +165,7 @@
+ };
+ 
+ #define CONFIG1_DESC_SIZE (9+9+5+5+4+5+7+9+7+7)
+-static uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
++static const uint8_t PROGMEM config1_descriptor[CONFIG1_DESC_SIZE] = {
+ 	// configuration descriptor, USB spec 9.6.3, page 264-266, Table 9-10
+ 	9, 					// bLength;
+ 	2,					// bDescriptorType;
+@@ -248,22 +249,22 @@
+ 	uint8_t bDescriptorType;
+ 	int16_t wString[];
+ };
+-static struct usb_string_descriptor_struct PROGMEM string0 = {
++static const struct usb_string_descriptor_struct PROGMEM string0 = {
+ 	4,
+ 	3,
+ 	{0x0409}
+ };
+-static struct usb_string_descriptor_struct PROGMEM string1 = {
++static const struct usb_string_descriptor_struct PROGMEM string1 = {
+ 	sizeof(STR_MANUFACTURER),
+ 	3,
+ 	STR_MANUFACTURER
+ };
+-static struct usb_string_descriptor_struct PROGMEM string2 = {
++static const struct usb_string_descriptor_struct PROGMEM string2 = {
+ 	sizeof(STR_PRODUCT),
+ 	3,
+ 	STR_PRODUCT
+ };
+-static struct usb_string_descriptor_struct PROGMEM string3 = {
++static const struct usb_string_descriptor_struct PROGMEM string3 = {
+ 	sizeof(STR_SERIAL_NUMBER),
+ 	3,
+ 	STR_SERIAL_NUMBER
+@@ -271,7 +272,7 @@
+ 
+ // This table defines which descriptor data is sent for each specific
+ // request from the host (in wValue and wIndex).
+-static struct descriptor_list_struct {
++static const struct descriptor_list_struct {
+ 	uint16_t	wValue;
+ 	uint16_t	wIndex;
+ 	const uint8_t	*addr;
+@@ -646,7 +647,9 @@
+ // communication
+ uint32_t usb_serial_get_baud(void)
+ {
+-	return *(uint32_t *)cdc_line_coding;
++	uint32_t res;
++	memcpy(&res, cdc_line_coding, sizeof(res));
++	return res;
+ }
+ uint8_t usb_serial_get_stopbits(void)
+ {
diff --git a/src/avr/Kconfig b/src/avr/Kconfig
index e0964676..5056e86a 100644
--- a/src/avr/Kconfig
+++ b/src/avr/Kconfig
@@ -12,6 +12,8 @@ choice
         bool "atmega168"
     config MACH_atmega644p
         bool "atmega644p"
+    config MACH_at90usb1286
+        bool "at90usb1286"
     config MACH_atmega1280
         bool "atmega1280"
     config MACH_atmega2560
@@ -22,6 +24,7 @@ config MCU
     string
     default "atmega168" if MACH_atmega168
     default "atmega644p" if MACH_atmega644p
+    default "at90usb1286" if MACH_at90usb1286
     default "atmega1280" if MACH_atmega1280
     default "atmega2560" if MACH_atmega2560
 
@@ -49,7 +52,12 @@ config AVR_STACK_SIZE
 config AVR_WATCHDOG
     bool "Support for automated reset on watchdog timeout"
     default y
+config AVR_USBSERIAL
+    bool
+    depends on MACH_at90usb1286
+    default y
 config AVR_SERIAL
+    depends on !AVR_USBSERIAL
     bool
     default y
 config SERIAL_BAUD
diff --git a/src/avr/Makefile b/src/avr/Makefile
index 758443da..c5e5dba1 100644
--- a/src/avr/Makefile
+++ b/src/avr/Makefile
@@ -9,6 +9,7 @@ LDFLAGS-y += -Wl,--relax
 # Add avr source files
 src-y += avr/main.c avr/timer.c avr/gpio.c avr/alloc.c
 src-$(CONFIG_AVR_WATCHDOG) += avr/watchdog.c
+src-$(CONFIG_AVR_USBSERIAL) += avr/usbserial.c ../lib/pjrc_usb_serial/usb_serial.c
 src-$(CONFIG_AVR_SERIAL) += avr/serial.c
 
 # Build the additional hex output file
diff --git a/src/avr/gpio.c b/src/avr/gpio.c
index d2cdfbd8..20598dc4 100644
--- a/src/avr/gpio.c
+++ b/src/avr/gpio.c
@@ -29,7 +29,10 @@ static volatile uint8_t * const digital_regs[] PROGMEM = {
 #endif
     &PINB, &PINC, &PIND,
 #ifdef PINE
-    &PINE, &PINF, &PING, &PINH, NULL, &PINJ, &PINK, &PINL
+    &PINE, &PINF,
+#endif
+#ifdef PING
+    &PING, &PINH, NULL, &PINJ, &PINK, &PINL
 #endif
 };
 
@@ -64,6 +67,17 @@ static const struct gpio_pwm_info pwm_regs[] PROGMEM = {
 //    { &OCR1B, &TCCR1A, &TCCR1B, 1<<COM1B1, GPIO('D', 4), 0               },
     { &OCR2A, &TCCR2A, &TCCR2B, 1<<COM2A1, GPIO('D', 7), GP_8BIT|GP_AFMT },
     { &OCR2B, &TCCR2A, &TCCR2B, 1<<COM2B1, GPIO('D', 6), GP_8BIT|GP_AFMT },
+#elif CONFIG_MACH_at90usb1286
+    { &OCR0A, &TCCR0A, &TCCR0B, 1<<COM0A1, GPIO('B', 7), GP_8BIT         },
+    { &OCR0B, &TCCR0A, &TCCR0B, 1<<COM0B1, GPIO('D', 0), GP_8BIT         },
+//    { &OCR1A, &TCCR1A, &TCCR1B, 1<<COM1A1, GPIO('B', 5), 0               },
+//    { &OCR1B, &TCCR1A, &TCCR1B, 1<<COM1B1, GPIO('B', 6), 0               },
+//    { &OCR1C, &TCCR1A, &TCCR1B, 1<<COM1C1, GPIO('B', 7), 0               },
+    { &OCR2A, &TCCR2A, &TCCR2B, 1<<COM2A1, GPIO('B', 4), GP_8BIT|GP_AFMT },
+    { &OCR2B, &TCCR2A, &TCCR2B, 1<<COM2B1, GPIO('D', 1), GP_8BIT|GP_AFMT },
+    { &OCR3A, &TCCR3A, &TCCR3B, 1<<COM3A1, GPIO('C', 6), 0               },
+    { &OCR3B, &TCCR3A, &TCCR3B, 1<<COM3B1, GPIO('C', 5), 0               },
+    { &OCR3C, &TCCR3A, &TCCR3B, 1<<COM3C1, GPIO('C', 4), 0               },
 #elif CONFIG_MACH_atmega1280 || CONFIG_MACH_atmega2560
     { &OCR0A, &TCCR0A, &TCCR0B, 1<<COM0A1, GPIO('B', 7), GP_8BIT         },
     { &OCR0B, &TCCR0A, &TCCR0B, 1<<COM0B1, GPIO('G', 5), GP_8BIT         },
@@ -95,6 +109,9 @@ static const struct gpio_adc_info adc_pins[] PROGMEM = {
 #elif CONFIG_MACH_atmega644p
     { GPIO('A', 0) }, { GPIO('A', 1) }, { GPIO('A', 2) }, { GPIO('A', 3) },
     { GPIO('A', 4) }, { GPIO('A', 5) }, { GPIO('A', 6) }, { GPIO('A', 7) },
+#elif CONFIG_MACH_at90usb1286
+    { GPIO('F', 0) }, { GPIO('F', 1) }, { GPIO('F', 2) }, { GPIO('F', 3) },
+    { GPIO('F', 4) }, { GPIO('F', 5) }, { GPIO('F', 6) }, { GPIO('F', 7) },
 #elif CONFIG_MACH_atmega1280 || CONFIG_MACH_atmega2560
     { GPIO('F', 0) }, { GPIO('F', 1) }, { GPIO('F', 2) }, { GPIO('F', 3) },
     { GPIO('F', 4) }, { GPIO('F', 5) }, { GPIO('F', 6) }, { GPIO('F', 7) },
@@ -107,7 +124,7 @@ static const struct gpio_adc_info adc_pins[] PROGMEM = {
 static const uint8_t SS = GPIO('B', 2), SCK = GPIO('B', 5), MOSI = GPIO('B', 3);
 #elif CONFIG_MACH_atmega644p
 static const uint8_t SS = GPIO('B', 4), SCK = GPIO('B', 7), MOSI = GPIO('B', 5);
-#elif CONFIG_MACH_atmega1280 || CONFIG_MACH_atmega2560
+#elif CONFIG_MACH_at90usb1286 || CONFIG_MACH_atmega1280 || CONFIG_MACH_atmega2560
 static const uint8_t SS = GPIO('B', 0), SCK = GPIO('B', 1), MOSI = GPIO('B', 2);
 #endif
 
diff --git a/src/avr/usbserial.c b/src/avr/usbserial.c
new file mode 100644
index 00000000..4cf1bd0f
--- /dev/null
+++ b/src/avr/usbserial.c
@@ -0,0 +1,65 @@
+// Wrappers for AVR usb serial.
+//
+// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include <avr/interrupt.h> // USART0_RX_vect
+#include <string.h> // memmove
+#include "../lib/pjrc_usb_serial/usb_serial.h"
+#include "sched.h" // DECL_INIT
+
+#define USBSERIAL_BUFFER_SIZE 64
+static char receive_buf[USBSERIAL_BUFFER_SIZE];
+static uint8_t receive_pos;
+static char transmit_buf[USBSERIAL_BUFFER_SIZE];
+
+static void
+usbserial_init(void)
+{
+    usb_init();
+}
+DECL_INIT(usbserial_init);
+
+// Return a buffer (and length) containing any incoming messages
+char *
+console_get_input(uint8_t *plen)
+{
+    for (;;) {
+        if (receive_pos >= sizeof(receive_buf))
+            break;
+        int16_t ret = usb_serial_getchar();
+        if (ret == -1)
+            break;
+        receive_buf[receive_pos++] = ret;
+    }
+    *plen = receive_pos;
+    return receive_buf;
+}
+
+// Remove from the receive buffer the given number of bytes
+void
+console_pop_input(uint8_t len)
+{
+    uint8_t needcopy = receive_pos - len;
+    if (needcopy)
+        memmove(receive_buf, &receive_buf[len], needcopy);
+    receive_pos = needcopy;
+}
+
+// Return an output buffer that the caller may fill with transmit messages
+char *
+console_get_output(uint8_t len)
+{
+    if (len > sizeof(transmit_buf))
+        return NULL;
+    return transmit_buf;
+}
+
+// Accept the given number of bytes added to the transmit buffer
+void
+console_push_output(uint8_t len)
+{
+    usb_serial_write((void*)transmit_buf, len);
+    usb_serial_flush_output();
+}