1 files changed, 110 insertions, 0 deletions
diff --git a/targets/arduino/wiring_analog.c b/targets/arduino/wiring_analog.c
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+++ b/targets/arduino/wiring_analog.c
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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
+
+  $Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
+*/
+
+#include "wiring_private.h"
+#include "pins_arduino.h"
+
+int analogRead(uint8_t pin)
+{
+	uint8_t low, high, ch = analogInPinToBit(pin);
+
+	// the low 4 bits of ADMUX select the ADC channel
+	ADMUX = (ADMUX & (unsigned int) 0xf0) | (ch & (unsigned int) 0x0f);
+
+	// 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_ATmega168__)
+	} else if (digitalPinToTimer(pin) == TIMER0A) {
+		// connect pwm to pin on timer 0, channel A
+		sbi(TCCR0A, COM0A1);
+		// set pwm duty
+		OCR0A = val;	
+	} else if (digitalPinToTimer(pin) == TIMER0B) {
+		// 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;
+#else
+	} else if (digitalPinToTimer(pin) == TIMER2) {
+		// connect pwm to pin on timer 2, channel B
+		sbi(TCCR2, COM21);
+		// set pwm duty
+		OCR2 = val;
+#endif
+	} else if (val < 128)
+		digitalWrite(pin, LOW);
+	else
+		digitalWrite(pin, HIGH);
+}