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+/*
+ SoftwareSerial.cpp - Software serial library
+ Copyright (c) 2006 David A. Mellis. All right reserved.
+
+ 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
+*/
+
+/******************************************************************************
+ * Includes
+ ******************************************************************************/
+
+#include "WConstants.h"
+#include "SoftwareSerial.h"
+
+/******************************************************************************
+ * Definitions
+ ******************************************************************************/
+
+/******************************************************************************
+ * Constructors
+ ******************************************************************************/
+
+SoftwareSerial::SoftwareSerial(uint8_t receivePin, uint8_t transmitPin)
+{
+ _receivePin = receivePin;
+ _transmitPin = transmitPin;
+ _baudRate = 0;
+}
+
+/******************************************************************************
+ * User API
+ ******************************************************************************/
+
+void SoftwareSerial::begin(long speed)
+{
+ _baudRate = speed;
+ _bitPeriod = 1000000 / _baudRate;
+
+ digitalWrite(_transmitPin, HIGH);
+ delayMicroseconds( _bitPeriod); // if we were low this establishes the end
+}
+
+int SoftwareSerial::read()
+{
+ int val = 0;
+ int bitDelay = _bitPeriod - clockCyclesToMicroseconds(50);
+
+ // one byte of serial data (LSB first)
+ // ...--\ /--\/--\/--\/--\/--\/--\/--\/--\/--...
+ // \--/\--/\--/\--/\--/\--/\--/\--/\--/
+ // start 0 1 2 3 4 5 6 7 stop
+
+ while (digitalRead(_receivePin));
+
+ // confirm that this is a real start bit, not line noise
+ if (digitalRead(_receivePin) == LOW) {
+ // frame start indicated by a falling edge and low start bit
+ // jump to the middle of the low start bit
+ delayMicroseconds(bitDelay / 2 - clockCyclesToMicroseconds(50));
+
+ // offset of the bit in the byte: from 0 (LSB) to 7 (MSB)
+ for (int offset = 0; offset < 8; offset++) {
+ // jump to middle of next bit
+ delayMicroseconds(bitDelay);
+
+ // read bit
+ val |= digitalRead(_receivePin) << offset;
+ }
+
+ delayMicroseconds(_bitPeriod);
+
+ return val;
+ }
+
+ return -1;
+}
+
+void SoftwareSerial::print(uint8_t b)
+{
+ if (_baudRate == 0)
+ return;
+
+ int bitDelay = _bitPeriod - clockCyclesToMicroseconds(50); // a digitalWrite is about 50 cycles
+ byte mask;
+
+ digitalWrite(_transmitPin, LOW);
+ delayMicroseconds(bitDelay);
+
+ for (mask = 0x01; mask; mask <<= 1) {
+ if (b & mask){ // choose bit
+ digitalWrite(_transmitPin,HIGH); // send 1
+ }
+ else{
+ digitalWrite(_transmitPin,LOW); // send 1
+ }
+ delayMicroseconds(bitDelay);
+ }
+
+ digitalWrite(_transmitPin, HIGH);
+ delayMicroseconds(bitDelay);
+}
+
+void SoftwareSerial::print(const char *s)
+{
+ while (*s)
+ print(*s++);
+}
+
+void SoftwareSerial::print(char c)
+{
+ print((uint8_t) c);
+}
+
+void SoftwareSerial::print(int n)
+{
+ print((long) n);
+}
+
+void SoftwareSerial::print(unsigned int n)
+{
+ print((unsigned long) n);
+}
+
+void SoftwareSerial::print(long n)
+{
+ if (n < 0) {
+ print('-');
+ n = -n;
+ }
+ printNumber(n, 10);
+}
+
+void SoftwareSerial::print(unsigned long n)
+{
+ printNumber(n, 10);
+}
+
+void SoftwareSerial::print(long n, int base)
+{
+ if (base == 0)
+ print((char) n);
+ else if (base == 10)
+ print(n);
+ else
+ printNumber(n, base);
+}
+
+void SoftwareSerial::println(void)
+{
+ print('\r');
+ print('\n');
+}
+
+void SoftwareSerial::println(char c)
+{
+ print(c);
+ println();
+}
+
+void SoftwareSerial::println(const char c[])
+{
+ print(c);
+ println();
+}
+
+void SoftwareSerial::println(uint8_t b)
+{
+ print(b);
+ println();
+}
+
+void SoftwareSerial::println(int n)
+{
+ print(n);
+ println();
+}
+
+void SoftwareSerial::println(long n)
+{
+ print(n);
+ println();
+}
+
+void SoftwareSerial::println(unsigned long n)
+{
+ print(n);
+ println();
+}
+
+void SoftwareSerial::println(long n, int base)
+{
+ print(n, base);
+ println();
+}
+
+// Private Methods /////////////////////////////////////////////////////////////
+
+void SoftwareSerial::printNumber(unsigned long n, uint8_t base)
+{
+ unsigned char buf[8 * sizeof(long)]; // Assumes 8-bit chars.
+ unsigned long i = 0;
+
+ if (n == 0) {
+ print('0');
+ return;
+ }
+
+ while (n > 0) {
+ buf[i++] = n % base;
+ n /= base;
+ }
+
+ for (; i > 0; i--)
+ print((char) (buf[i - 1] < 10 ? '0' + buf[i - 1] : 'A' + buf[i - 1] - 10));
+}