Quadrotor

/*

  wiring_digital.c - digital input and output functions

  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 $

*/

#define ARDUINO_MAIN

#include "wiring_private.h"

#include "pins_arduino.h"

void pinMode(uint8_t pin, uint8_t mode)

{

        uint8_t bit = digitalPinToBitMask(pin);

        uint8_t port = digitalPinToPort(pin);

        volatile uint8_t *reg;

        if (port == NOT_A_PIN) return;

        // JWS: can I let the optimizer do this?

        reg = portModeRegister(port);

        if (mode == INPUT) { 

                uint8_t oldSREG = SREG;

                cli();

                *reg &= ~bit;

                SREG = oldSREG;

        } else {

                uint8_t oldSREG = SREG;

                cli();

                *reg |= bit;

                SREG = oldSREG;

        }

}

// Forcing this inline keeps the callers from having to push their own stuff

// on the stack. It is a good performance win and only takes 1 more byte per

// user than calling. (It will take more bytes on the 168.)

//

// But shouldn't this be moved into pinMode? Seems silly to check and do on

// each digitalread or write.

//

// Mark Sproul:

// - Removed inline. Save 170 bytes on atmega1280

// - changed to a switch statment; added 32 bytes but much easier to read and maintain.

// - Added more #ifdefs, now compiles for atmega645

//

//static inline void turnOffPWM(uint8_t timer) __attribute__ ((always_inline));

//static inline void turnOffPWM(uint8_t timer)

static void turnOffPWM(uint8_t timer)

{

        switch (timer)

        {

                #if defined(TCCR1A) && defined(COM1A1)

                case TIMER1A:   cbi(TCCR1A, COM1A1);    break;

                #endif

                #if defined(TCCR1A) && defined(COM1B1)

                case TIMER1B:   cbi(TCCR1A, COM1B1);    break;

                #endif

                #if defined(TCCR2) && defined(COM21)

                case  TIMER2:   cbi(TCCR2, COM21);      break;

                #endif

                #if defined(TCCR0A) && defined(COM0A1)

                case  TIMER0A:  cbi(TCCR0A, COM0A1);    break;

                #endif

                #if defined(TIMER0B) && defined(COM0B1)

                case  TIMER0B:  cbi(TCCR0A, COM0B1);    break;

                #endif

                #if defined(TCCR2A) && defined(COM2A1)

                case  TIMER2A:  cbi(TCCR2A, COM2A1);    break;

                #endif

                #if defined(TCCR2A) && defined(COM2B1)

                case  TIMER2B:  cbi(TCCR2A, COM2B1);    break;

                #endif

                #if defined(TCCR3A) && defined(COM3A1)

                case  TIMER3A:  cbi(TCCR3A, COM3A1);    break;

                #endif

                #if defined(TCCR3A) && defined(COM3B1)

                case  TIMER3B:  cbi(TCCR3A, COM3B1);    break;

                #endif

                #if defined(TCCR3A) && defined(COM3C1)

                case  TIMER3C:  cbi(TCCR3A, COM3C1);    break;

                #endif

                #if defined(TCCR4A) && defined(COM4A1)

                case  TIMER4A:  cbi(TCCR4A, COM4A1);    break;

                #endif

                #if defined(TCCR4A) && defined(COM4B1)

                case  TIMER4B:  cbi(TCCR4A, COM4B1);    break;

                #endif

                #if defined(TCCR4A) && defined(COM4C1)

                case  TIMER4C:  cbi(TCCR4A, COM4C1);    break;

                #endif

                #if defined(TCCR5A)

                case  TIMER5A:  cbi(TCCR5A, COM5A1);    break;

                case  TIMER5B:  cbi(TCCR5A, COM5B1);    break;

                case  TIMER5C:  cbi(TCCR5A, COM5C1);    break;

                #endif

        }

}

void digitalWrite(uint8_t pin, uint8_t val)

{

        uint8_t timer = digitalPinToTimer(pin);

        uint8_t bit = digitalPinToBitMask(pin);

        uint8_t port = digitalPinToPort(pin);

        volatile uint8_t *out;

        if (port == NOT_A_PIN) return;

        // If the pin that support PWM output, we need to turn it off

        // before doing a digital write.

        if (timer != NOT_ON_TIMER) turnOffPWM(timer);

        out = portOutputRegister(port);

        uint8_t oldSREG = SREG;

        cli();

        if (val == LOW) {

                *out &= ~bit;

        } else {

                *out |= bit;

        }

        SREG = oldSREG;

}

int digitalRead(uint8_t pin)

{

        uint8_t timer = digitalPinToTimer(pin);

        uint8_t bit = digitalPinToBitMask(pin);

        uint8_t port = digitalPinToPort(pin);

        if (port == NOT_A_PIN) return LOW;

        // If the pin that support PWM output, we need to turn it off

        // before getting a digital reading.

        if (timer != NOT_ON_TIMER) turnOffPWM(timer);

        if (*portInputRegister(port) & bit) return HIGH;

        return LOW;

}