YWrobot CYB：创建页面，内容为“

 /*   wiring_digital.c - digital input and output functions   Part of Arduino - http://www.arduino.cc/    Copyright (c) 2005-2006 David A. Me...”

2016-04-25T02:05:05Z

新页面

<pre style="color:blue">
/*
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, *out;

if (port == NOT_A_PIN) return;

// JWS: can I let the optimizer do this?
reg = portModeRegister(port);
out = portOutputRegister(port);

if (mode == INPUT) {
uint8_t oldSREG = SREG;
cli();
*reg &= ~bit;
*out &= ~bit;
SREG = oldSREG;
} else if (mode == INPUT_PULLUP) {
uint8_t oldSREG = SREG;
cli();
*reg &= ~bit;
*out |= 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(TCCR4C) && defined(COM4D1)
case TIMER4D: cbi(TCCR4C, COM4D1); 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;
}

</pre>

Wiring digital.c - 版本历史

YWrobot CYB：创建页面，内容为“
/* wiring_digital.c - digital input and output functions Part of Arduino - http://www.arduino.cc/ Copyright (c) 2005-2006 David A. Me...”