extint.h

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/*! \file extint.h \brief External-Interrupt function library. */
//*****************************************************************************
//
// File Name    : 'extint.h'
// Title        : External-Interrupt function library
// Author       : Pascal Stang - Copyright (C) 2002-2004
// Created      : 5/10/2002
// Revised      : 11/16/2004
// Version      : 1.0
// Target MCU   : Atmel AVR Series
// Editor Tabs  : 4
//
// Notes:   This library provides convenient standardized configuration and
//          access to external interrupts.  The library is designed to make
//          it possible to write code that uses external interrupts without
//          digging into the processor datasheets to find register names and
//          bit-defines.  The library also strives to allow code which uses
//          external interrupts to more easily cross-compile between different
//          microcontrollers.
//
//          NOTE: Using this library has certain advantages, but also adds
//          overhead and latency to interrupt servicing.  If the smallest
//          code size or fastest possible latency is needed, do NOT use this
//          library; link your interrupts directly.
//
//*****************************************************************************

#ifndef EXTINT_H
#define EXTINT_H

#include "global.h"

// constants/macros/typdefs

// interrupt macros for attaching user functions to external interrupts
// use these with extintAttach( intNum, function )
#define EXTINT0                 0x00    ///< External Interrupt 0
#define EXTINT1                 0x01    ///< External Interrupt 1
#define EXTINT2                 0x02    ///< External Interrupt 2
#define EXTINT3                 0x03    ///< External Interrupt 3
#define EXTINT4                 0x04    ///< External Interrupt 4
#define EXTINT5                 0x05    ///< External Interrupt 5
#define EXTINT6                 0x06    ///< External Interrupt 6
#define EXTINT7                 0x07    ///< External Interrupt 7

#define EXTINT_LEVEL_LOW        0x00    ///< Trigger on low level
#define EXTINT_EDGE_ANY         0x01    ///< Trigger on any edge
#define EXTINT_EDGE_FALLING     0x02    ///< Trigger on falling edge
#define EXTINT_EDGE_RISING      0x03    ///< Trigger on rising edge

// type of interrupt handler to use
// *do not change unless you know what you're doing
// Value may be SIGNAL or INTERRUPT
#ifndef EXTINT_INTERRUPT_HANDLER
#define EXTINT_INTERRUPT_HANDLER    SIGNAL
#endif

// processor-adaptive defines
// mainstream AVR processors generally have 1,2,3, or 8 external interrupts
// (if someone has a better idea of how to manage this, let me know)
#ifdef SIG_INTERRUPT7
    #define EXTINT_NUM_INTERRUPTS   8
#else
#ifdef SIG_INTERRUPT2
    #define EXTINT_NUM_INTERRUPTS   3
#else
#ifdef SIG_INTERRUPT1
    #define EXTINT_NUM_INTERRUPTS   2
#else
    #define EXTINT_NUM_INTERRUPTS   1
#endif
#endif
#endif

// functions

//! initializes extint library
void extintInit(void);

//! Configure external interrupt trigger
void extintConfigure(u08 interruptNum, u08 configuration);

// extintAttach and extintDetach commands
//      These functions allow the attachment (or detachment) of any user
//      function to an external interrupt.  "Attaching" one of your own
//      functions to an interrupt means that it will be called whenever
//      that interrupt is triggered.  Example usage:
//
//      extintAttach(EXTINT0, myInterruptHandler);
//      extintDetach(EXTINT0);
//
//      extintAttach causes the myInterruptHandler() to be attached, and therefore
//      execute, whenever the corresponding interrupt occurs.  extintDetach removes
//      the association and executes no user function when the interrupt occurs.
//      myInterruptFunction must be defined with no return value and no arguments:
//
//      void myInterruptHandler(void) { ... }

//! Attach a user function to an external interrupt
void extintAttach(u08 interruptNum, void (*userHandler)(void) );
//! Detach a user function from an external interrupt
void extintDetach(u08 interruptNum);

#endif

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