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+/*
+ 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
+
+ Modified 28 September 2010 by Mark Sproul
+*/
+
+#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;
+
+#if defined(analogPinToChannel)
+#if defined(__AVR_ATmega32U4__)
+ if (pin >= 18) pin -= 18; // allow for channel or pin numbers
+#endif
+ pin = analogPinToChannel(pin);
+#elif defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+ if (pin >= 54) pin -= 54; // allow for channel or pin numbers
+#elif defined(__AVR_ATmega32U4__)
+ if (pin >= 18) pin -= 18; // allow for channel or pin numbers
+#elif defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega644__) || defined(__AVR_ATmega644A__) || defined(__AVR_ATmega644P__) || defined(__AVR_ATmega644PA__)
+ if (pin >= 24) pin -= 24; // allow for channel or pin numbers
+#else
+ if (pin >= 14) pin -= 14; // allow for channel or pin numbers
+#endif
+
+#if defined(ADCSRB) && defined(MUX5)
+ // 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
+
+ // 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).
+#if defined(ADMUX)
+#if defined(__AVR_ATtiny25__) || defined(__AVR_ATtiny45__) || defined(__AVR_ATtiny85__)
+ ADMUX = (analog_reference << 4) | (pin & 0x07);
+#else
+ ADMUX = (analog_reference << 6) | (pin & 0x07);
+#endif
+#endif
+
+ // without a delay, we seem to read from the wrong channel
+ //delay(1);
+
+#if defined(ADCSRA) && defined(ADCL)
+ // 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;
+#else
+ // we dont have an ADC, return 0
+ low = 0;
+ high = 0;
+#endif
+
+ // 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 (val == 0)
+ {
+ digitalWrite(pin, LOW);
+ }
+ else if (val == 255)
+ {
+ digitalWrite(pin, HIGH);
+ }
+ else
+ {
+ switch(digitalPinToTimer(pin))
+ {
+ // XXX fix needed for atmega8
+ #if defined(TCCR0) && defined(COM00) && !defined(__AVR_ATmega8__)
+ case TIMER0A:
+ // connect pwm to pin on timer 0
+ sbi(TCCR0, COM00);
+ OCR0 = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR0A) && defined(COM0A1)
+ case TIMER0A:
+ // connect pwm to pin on timer 0, channel A
+ sbi(TCCR0A, COM0A1);
+ OCR0A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR0A) && defined(COM0B1)
+ case TIMER0B:
+ // connect pwm to pin on timer 0, channel B
+ sbi(TCCR0A, COM0B1);
+ OCR0B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR1A) && defined(COM1A1)
+ case TIMER1A:
+ // connect pwm to pin on timer 1, channel A
+ sbi(TCCR1A, COM1A1);
+ OCR1A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR1A) && defined(COM1B1)
+ case TIMER1B:
+ // connect pwm to pin on timer 1, channel B
+ sbi(TCCR1A, COM1B1);
+ OCR1B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR1A) && defined(COM1C1)
+ case TIMER1C:
+ // connect pwm to pin on timer 1, channel B
+ sbi(TCCR1A, COM1C1);
+ OCR1C = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR2) && defined(COM21)
+ case TIMER2:
+ // connect pwm to pin on timer 2
+ sbi(TCCR2, COM21);
+ OCR2 = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR2A) && defined(COM2A1)
+ case TIMER2A:
+ // connect pwm to pin on timer 2, channel A
+ sbi(TCCR2A, COM2A1);
+ OCR2A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR2A) && defined(COM2B1)
+ case TIMER2B:
+ // connect pwm to pin on timer 2, channel B
+ sbi(TCCR2A, COM2B1);
+ OCR2B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR3A) && defined(COM3A1)
+ case TIMER3A:
+ // connect pwm to pin on timer 3, channel A
+ sbi(TCCR3A, COM3A1);
+ OCR3A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR3A) && defined(COM3B1)
+ case TIMER3B:
+ // connect pwm to pin on timer 3, channel B
+ sbi(TCCR3A, COM3B1);
+ OCR3B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR3A) && defined(COM3C1)
+ case TIMER3C:
+ // connect pwm to pin on timer 3, channel C
+ sbi(TCCR3A, COM3C1);
+ OCR3C = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR4A)
+ case TIMER4A:
+ //connect pwm to pin on timer 4, channel A
+ sbi(TCCR4A, COM4A1);
+ #if defined(COM4A0) // only used on 32U4
+ cbi(TCCR4A, COM4A0);
+ #endif
+ OCR4A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR4A) && defined(COM4B1)
+ case TIMER4B:
+ // connect pwm to pin on timer 4, channel B
+ sbi(TCCR4A, COM4B1);
+ OCR4B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR4A) && defined(COM4C1)
+ case TIMER4C:
+ // connect pwm to pin on timer 4, channel C
+ sbi(TCCR4A, COM4C1);
+ OCR4C = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR4C) && defined(COM4D1)
+ case TIMER4D:
+ // connect pwm to pin on timer 4, channel D
+ sbi(TCCR4C, COM4D1);
+ #if defined(COM4D0) // only used on 32U4
+ cbi(TCCR4C, COM4D0);
+ #endif
+ OCR4D = val; // set pwm duty
+ break;
+ #endif
+
+
+ #if defined(TCCR5A) && defined(COM5A1)
+ case TIMER5A:
+ // connect pwm to pin on timer 5, channel A
+ sbi(TCCR5A, COM5A1);
+ OCR5A = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR5A) && defined(COM5B1)
+ case TIMER5B:
+ // connect pwm to pin on timer 5, channel B
+ sbi(TCCR5A, COM5B1);
+ OCR5B = val; // set pwm duty
+ break;
+ #endif
+
+ #if defined(TCCR5A) && defined(COM5C1)
+ case TIMER5C:
+ // connect pwm to pin on timer 5, channel C
+ sbi(TCCR5A, COM5C1);
+ OCR5C = val; // set pwm duty
+ break;
+ #endif
+
+ case NOT_ON_TIMER:
+ default:
+ if (val < 128) {
+ digitalWrite(pin, LOW);
+ } else {
+ digitalWrite(pin, HIGH);
+ }
+ }
+ }
+}
+