| /* |
| 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 |
| |
| $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; |
| |
| #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) |
| if (pin >= 54) pin -= 54; // 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) |
| ADMUX = (analog_reference << 6) | (pin & 0x07); |
| #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(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) && defined(COM4A1) |
| case TIMER4A: |
| // connect pwm to pin on timer 4, channel A |
| sbi(TCCR4A, COM4A1); |
| 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(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); |
| } |
| } |
| } |
| } |