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diff --git a/src/core/SoftwareSerial.cpp b/src/core/SoftwareSerial.cpp
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+/*
+ * This class is porting arduino's SoftwareSerial for eXodusino
+ *
+ * Created on: 2012/03/17
+ * @author nucho
+ */
+
+/*
+ SoftwareSerial.cpp (formerly NewSoftSerial.cpp) -
+ Multi-instance software serial library for Arduino/Wiring
+ -- Interrupt-driven receive and other improvements by ladyada
+ (http://ladyada.net)
+ -- Tuning, circular buffer, derivation from class Print/Stream,
+ multi-instance support, porting to 8MHz processors,
+ various optimizations, PROGMEM delay tables, inverse logic and
+ direct port writing by Mikal Hart (http://www.arduiniana.org)
+ -- Pin change interrupt macros by Paul Stoffregen (http://www.pjrc.com)
+ -- 20MHz processor support by Garrett Mace (http://www.macetech.com)
+ -- ATmega1280/2560 support by Brett Hagman (http://www.roguerobotics.com/)
+
+ This library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ This library 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with this library; if not, write to the Free Software
+ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+
+ The latest version of this library can always be found at
+ http://arduiniana.org.
+ */
+
+#include "SoftwareSerial.h"
+#include "gpio.h"
+#include "delay.h"
+//
+// Lookup table
+//
+typedef struct _DELAY_TABLE {
+	long baud;
+	unsigned short rx_delay_centering;
+	unsigned short rx_delay_intrabit;
+	unsigned short rx_delay_stopbit;
+	unsigned short tx_delay;
+} DELAY_TABLE;
+
+static const DELAY_TABLE table[] = {
+//  baud    rxcenter   rxintra    rxstop    tx
+		{ 38400, 11, 23, 23, 23, },//no support
+		{ 19200, 23, 47, 47, 49, },//no support
+		{ 9600, 50,100, 100, 100, },
+		{ 4800, 101, 202, 202, 202, },
+};
+
+
+//
+// Debugging
+//
+// This function generates a brief pulse
+// for debugging or measuring on an oscilloscope.
+inline void DebugPulse(uint8_t pin, uint8_t count) {
+	//#if _DEBUG
+	//		volatile uint8_t *pport = portOutputRegister(digitalPinToPort(pin));
+	//
+	//		uint8_t val = *pport;
+	//		while (count--)
+	//		{
+	//			*pport = val | digitalPinToBitMask(pin);
+	//			*pport = val;
+	//		}
+	//#endif
+}
+
+//
+// Statics
+//
+SoftwareSerial *SoftwareSerial::active_object = 0;
+char SoftwareSerial::_receive_buffer[_SS_MAX_RX_BUFF];
+volatile uint8_t SoftwareSerial::_receive_buffer_tail = 0;
+volatile uint8_t SoftwareSerial::_receive_buffer_head = 0;
+
+//
+// Private methods
+//
+
+// This function sets the current object as the "listening"
+// one and returns true if it replaces another
+bool SoftwareSerial::listen() {
+	if (active_object != this) {
+		_buffer_overflow = false;
+
+		_receive_buffer_head = _receive_buffer_tail = 0;
+		active_object = this;
+		return true;
+	}
+
+	return false;
+}
+
+//
+// The receive routine called by the interrupt handler
+//
+void SoftwareSerial::recv() {
+	uint8_t d = 0;
+
+	// If RX line is high, then we don't see any start bit
+	// so interrupt is probably not for us
+	if (_inverse_logic ? digitalRead(_receivePin) : !digitalRead(_receivePin)) {
+		// Wait approximately 1/2 of a bit width to "center" the sample
+		delayMicroseconds(_rx_delay_centering);
+
+		DebugPulse(4, 1);
+
+		// Read each of the 8 bits
+		for (uint8_t i = 0x1; i; i <<= 1) {
+			delayMicroseconds(_rx_delay_intrabit);
+			DebugPulse(4, 1);
+			uint8_t noti = ~i;
+			if (digitalRead(_receivePin))
+				d |= i;
+			else
+				// else clause added to ensure function timing is ~balanced
+				d &= noti;
+		}
+
+		// skip the stop bit
+		delayMicroseconds(_rx_delay_stopbit);
+		DebugPulse(4, 1);
+
+		if (_inverse_logic)
+			d = ~d;
+
+		// if buffer full, set the overflow flag and return
+		if ((_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF
+				!= _receive_buffer_head) {
+			// save new data in buffer: tail points to where byte goes
+			_receive_buffer[_receive_buffer_tail] = d; // save new byte
+			_receive_buffer_tail = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
+		} else {
+			_buffer_overflow = true;
+		}
+	}
+}
+// Interrupt handling
+//
+
+/* static */
+inline void SoftwareSerial::handle_interrupt() {
+	if (active_object) {
+		active_object->recv();
+	}
+}
+
+//
+// Constructor
+//
+SoftwareSerial::SoftwareSerial(uint8_t receivePin, uint8_t transmitPin,
+		bool inverse_logic /* = false */) :
+	_rx_delay_centering(0), _rx_delay_intrabit(0), _rx_delay_stopbit(0),
+			_tx_delay(0), _buffer_overflow(false),
+			_inverse_logic(inverse_logic) {
+	setTX(transmitPin);
+	setRX(receivePin);
+}
+
+//
+// Destructor
+//
+SoftwareSerial::~SoftwareSerial() {
+	end();
+}
+
+void SoftwareSerial::setTX(uint8_t tx) {
+	if (tx >= 0) {
+		pinMode(tx, OUTPUT);
+		digitalWrite(tx, HIGH);
+	}
+	_transmitPin = tx;
+}
+
+void SoftwareSerial::setRX(uint8_t rx) {
+	if (rx >= 0) {
+		if (!_inverse_logic) {
+			//TODO:pin pullup
+		} else {
+			//TODO:pin pulldown
+		}
+	}
+	_receivePin = rx;
+}
+
+//
+// Public methods
+//
+
+void SoftwareSerial::begin(long speed) {
+	_rx_delay_centering = _rx_delay_intrabit = _rx_delay_stopbit = _tx_delay
+			= 0;
+
+	for (unsigned i = 0; i < sizeof(table) / sizeof(table[0]); ++i) {
+		long baud = table[i].baud;
+		if (baud == speed) {
+			_rx_delay_centering = table[i].rx_delay_centering;
+			_rx_delay_intrabit = table[i].rx_delay_intrabit;
+			_rx_delay_stopbit = table[i].rx_delay_stopbit;
+			_tx_delay = table[i].tx_delay;
+			break;
+		}
+	}
+	// Set up RX interrupts, but only if we have a valid RX baud rate
+	if (_rx_delay_stopbit && _receivePin > 0) {
+		attachInterrupt(_receivePin, SoftwareSerial::handle_interrupt, FALLING);
+		delayMicroseconds(_tx_delay);// if we were low this establishes the end
+	}
+
+	listen();
+}
+
+void SoftwareSerial::end() {
+	if (_receivePin > 0) {
+		detachInterrupt(_receivePin);
+	}
+}
+
+// Read data from buffer
+int SoftwareSerial::read() {
+	if (!isListening())
+		return -1;
+
+	// Empty buffer?
+	if (_receive_buffer_head == _receive_buffer_tail)
+		return -1;
+
+	// Read from "head"
+	uint8_t d = _receive_buffer[_receive_buffer_head]; // grab next byte
+	_receive_buffer_head = (_receive_buffer_head + 1) % _SS_MAX_RX_BUFF;
+	return d;
+}
+
+int SoftwareSerial::available() {
+	if (!isListening())
+		return 0;
+
+	return (_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head)
+			% _SS_MAX_RX_BUFF;
+}
+
+void SoftwareSerial::write(const char c) {
+	if (_tx_delay == 0) {
+		return;
+	}
+	if (_transmitPin < 0) {
+		return;
+	}
+
+	// Write the start bit
+	digitalWrite(_transmitPin, _inverse_logic ? HIGH : LOW);
+	delayMicroseconds(_tx_delay);
+
+	// Write each of the 8 bits
+	if (_inverse_logic) {
+		for (uint8_t mask = 0x01; mask; mask <<= 1) {
+			if (c & mask) // choose bit
+				digitalWrite(_transmitPin, LOW); // send 1
+			else
+				digitalWrite(_transmitPin, HIGH); // send 0
+
+			delayMicroseconds(_tx_delay);
+		}
+
+		digitalWrite(_transmitPin, LOW); // restore pin to natural state
+	} else {
+		for (uint8_t mask = 0x01; mask; mask <<= 1) {
+			if (c & mask) // choose bit
+				digitalWrite(_transmitPin, HIGH); // send 1
+			else
+				digitalWrite(_transmitPin, LOW); // send 0
+
+			delayMicroseconds(_tx_delay);
+		}
+
+		digitalWrite(_transmitPin, HIGH); // restore pin to natural state
+	}
+
+	delayMicroseconds(_tx_delay);
+}
+
+void SoftwareSerial::flush() {
+	if (!isListening())
+		return;
+
+	_receive_buffer_head = _receive_buffer_tail = 0;
+}
+
+int SoftwareSerial::peek() {
+	if (!isListening())
+		return -1;
+
+	// Empty buffer?
+	if (_receive_buffer_head == _receive_buffer_tail)
+		return -1;
+
+	// Read from "head"
+	return _receive_buffer[_receive_buffer_head];
+}