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96 lines
2.8 KiB
C
96 lines
2.8 KiB
C
13 years ago
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/*
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wiring_digital.c - digital input and output functions
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Part of Arduino - http://www.arduino.cc/
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Copyright (c) 2005-2006 David A. Mellis
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General
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Public License along with this library; if not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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Boston, MA 02111-1307 USA
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$Id: wiring.c 248 2007-02-03 15:36:30Z mellis $
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*/
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#include "wiring_private.h"
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#include "pins_arduino.h"
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void pinMode(uint8_t pin, uint8_t mode)
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{
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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volatile uint8_t *reg;
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if (port == NOT_A_PIN) return;
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// JWS: can I let the optimizer do this?
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reg = portModeRegister(port);
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if (mode == INPUT) *reg &= ~bit;
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else *reg |= bit;
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}
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// Forcing this inline keeps the callers from having to push their own stuff
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// on the stack. It is a good performance win and only takes 1 more byte per
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// user than calling. (It will take more bytes on the 168.)
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//
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// But shouldn't this be moved into pinMode? Seems silly to check and do on
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// each digitalread or write.
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//
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static inline void turnOffPWM(uint8_t timer) __attribute__ ((always_inline));
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static inline void turnOffPWM(uint8_t timer)
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{
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if (timer == TIMER0A) cbi(TCCR0A, COM0A1);
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if (timer == TIMER0B) cbi(TCCR0A, COM0B1);
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if (timer == TIMER1A) cbi(TCCR1A, COM1A1);
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if (timer == TIMER1B) cbi(TCCR1A, COM1B1);
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if (timer == TIMER2A) cbi(TCCR2A, COM2A1);
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if (timer == TIMER2B) cbi(TCCR2A, COM2B1);
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}
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void digitalWrite(uint8_t pin, uint8_t val)
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{
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uint8_t timer = digitalPinToTimer(pin);
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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volatile uint8_t *out;
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if (port == NOT_A_PIN) return;
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// If the pin that support PWM output, we need to turn it off
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// before doing a digital write.
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if (timer != NOT_ON_TIMER) turnOffPWM(timer);
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out = portOutputRegister(port);
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if (val == LOW) *out &= ~bit;
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else *out |= bit;
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}
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int digitalRead(uint8_t pin)
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{
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uint8_t timer = digitalPinToTimer(pin);
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uint8_t bit = digitalPinToBitMask(pin);
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uint8_t port = digitalPinToPort(pin);
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if (port == NOT_A_PIN) return LOW;
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// If the pin that support PWM output, we need to turn it off
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// before getting a digital reading.
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if (timer != NOT_ON_TIMER) turnOffPWM(timer);
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if (*portInputRegister(port) & bit) return HIGH;
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return LOW;
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}
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