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Diffstat (limited to 'core/wiring_analog.c')
| -rwxr-xr-x | core/wiring_analog.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/core/wiring_analog.c b/core/wiring_analog.c new file mode 100755 index 0000000..529ad52 --- /dev/null +++ b/core/wiring_analog.c @@ -0,0 +1,179 @@ +/* + wiring_analog.c - analog input and output + Part of Arduino - http://www.arduino.cc/ + + Copyright (c) 2005-2006 David A. Mellis + + 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., 59 Temple Place, Suite 330, + Boston, MA 02111-1307 USA + + $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $ +*/ + +#include "wiring_private.h" +#include "pins_arduino.h" + +uint8_t analog_reference = DEFAULT; + +void analogReference(uint8_t mode) +{ + // can't actually set the register here because the default setting + // will connect AVCC and the AREF pin, which would cause a short if + // there's something connected to AREF. + analog_reference = mode; +} + +int analogRead(uint8_t pin) +{ + uint8_t low, high; + + // set the analog reference (high two bits of ADMUX) and select the + // channel (low 4 bits). this also sets ADLAR (left-adjust result) + // to 0 (the default). + ADMUX = (analog_reference << 6) | (pin & 0x07); + +#if defined(__AVR_ATmega1280__) + // the MUX5 bit of ADCSRB selects whether we're reading from channels + // 0 to 7 (MUX5 low) or 8 to 15 (MUX5 high). + ADCSRB = (ADCSRB & ~(1 << MUX5)) | (((pin >> 3) & 0x01) << MUX5); +#endif + + // without a delay, we seem to read from the wrong channel + //delay(1); + + // start the conversion + sbi(ADCSRA, ADSC); + + // ADSC is cleared when the conversion finishes + while (bit_is_set(ADCSRA, ADSC)); + + // we have to read ADCL first; doing so locks both ADCL + // and ADCH until ADCH is read. reading ADCL second would + // cause the results of each conversion to be discarded, + // as ADCL and ADCH would be locked when it completed. + low = ADCL; + high = ADCH; + + // combine the two bytes + return (high << 8) | low; +} + +// Right now, PWM output only works on the pins with +// hardware support. These are defined in the appropriate +// pins_*.c file. For the rest of the pins, we default +// to digital output. +void analogWrite(uint8_t pin, int val) +{ + // We need to make sure the PWM output is enabled for those pins + // that support it, as we turn it off when digitally reading or + // writing with them. Also, make sure the pin is in output mode + // for consistenty with Wiring, which doesn't require a pinMode + // call for the analog output pins. + pinMode(pin, OUTPUT); + + if (digitalPinToTimer(pin) == TIMER1A) { + // connect pwm to pin on timer 1, channel A + sbi(TCCR1A, COM1A1); + // set pwm duty + OCR1A = val; + } else if (digitalPinToTimer(pin) == TIMER1B) { + // connect pwm to pin on timer 1, channel B + sbi(TCCR1A, COM1B1); + // set pwm duty + OCR1B = val; +#if defined(__AVR_ATmega8__) + } else if (digitalPinToTimer(pin) == TIMER2) { + // connect pwm to pin on timer 2, channel B + sbi(TCCR2, COM21); + // set pwm duty + OCR2 = val; +#else + } else if (digitalPinToTimer(pin) == TIMER0A) { + if (val == 0) { + digitalWrite(pin, LOW); + } else { + // connect pwm to pin on timer 0, channel A + sbi(TCCR0A, COM0A1); + // set pwm duty + OCR0A = val; + } + } else if (digitalPinToTimer(pin) == TIMER0B) { + if (val == 0) { + digitalWrite(pin, LOW); + } else { + // connect pwm to pin on timer 0, channel B + sbi(TCCR0A, COM0B1); + // set pwm duty + OCR0B = val; + } + } else if (digitalPinToTimer(pin) == TIMER2A) { + // connect pwm to pin on timer 2, channel A + sbi(TCCR2A, COM2A1); + // set pwm duty + OCR2A = val; + } else if (digitalPinToTimer(pin) == TIMER2B) { + // connect pwm to pin on timer 2, channel B + sbi(TCCR2A, COM2B1); + // set pwm duty + OCR2B = val; +#endif +#if defined(__AVR_ATmega1280__) + // XXX: need to handle other timers here + } else if (digitalPinToTimer(pin) == TIMER3A) { + // connect pwm to pin on timer 3, channel A + sbi(TCCR3A, COM3A1); + // set pwm duty + OCR3A = val; + } else if (digitalPinToTimer(pin) == TIMER3B) { + // connect pwm to pin on timer 3, channel B + sbi(TCCR3A, COM3B1); + // set pwm duty + OCR3B = val; + } else if (digitalPinToTimer(pin) == TIMER3C) { + // connect pwm to pin on timer 3, channel C + sbi(TCCR3A, COM3C1); + // set pwm duty + OCR3C = val; + } else if (digitalPinToTimer(pin) == TIMER4A) { + // connect pwm to pin on timer 4, channel A + sbi(TCCR4A, COM4A1); + // set pwm duty + OCR4A = val; + } else if (digitalPinToTimer(pin) == TIMER4B) { + // connect pwm to pin on timer 4, channel B + sbi(TCCR4A, COM4B1); + // set pwm duty + OCR4B = val; + } else if (digitalPinToTimer(pin) == TIMER4C) { + // connect pwm to pin on timer 4, channel C + sbi(TCCR4A, COM4C1); + // set pwm duty + OCR4C = val; + } else if (digitalPinToTimer(pin) == TIMER5A) { + // connect pwm to pin on timer 5, channel A + sbi(TCCR5A, COM5A1); + // set pwm duty + OCR5A = val; + } else if (digitalPinToTimer(pin) == TIMER5B) { + // connect pwm to pin on timer 5, channel B + sbi(TCCR5A, COM5B1); + // set pwm duty + OCR5B = val; +#endif + } else if (val < 128) + digitalWrite(pin, LOW); + else + digitalWrite(pin, HIGH); +} |