diff options
author | David A. Mellis <d.mellis@arduino.cc> | 2007-10-06 13:02:43 +0000 |
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committer | David A. Mellis <d.mellis@arduino.cc> | 2007-10-06 13:02:43 +0000 |
commit | 179fcdbda432ff33a921a70994087b08b2a79caa (patch) | |
tree | db62b71d303b5b13876773552451406b13cc66cf /core/libraries/SoftwareSerial/SoftwareSerial.cpp |
Moving things around - creating the hardware directory and sticking all the avr code, etc. in there.
Diffstat (limited to 'core/libraries/SoftwareSerial/SoftwareSerial.cpp')
-rwxr-xr-x | core/libraries/SoftwareSerial/SoftwareSerial.cpp | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/core/libraries/SoftwareSerial/SoftwareSerial.cpp b/core/libraries/SoftwareSerial/SoftwareSerial.cpp new file mode 100755 index 0000000..6df04d2 --- /dev/null +++ b/core/libraries/SoftwareSerial/SoftwareSerial.cpp @@ -0,0 +1,227 @@ +/* + 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)); +} |