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Arduino/build/shared/lib/avrlib/rtc.c
2005-08-25 21:06:28 +00:00

132 lines
3.5 KiB
C
Executable File

/*! \file rtc.c \brief Real-time clock function library. */
//*****************************************************************************
//
// File Name : 'rtc.c'
// Title : Real-time clock function library
// Author : Pascal Stang - Copyright (C) 2002
// Created : 5/10/2002
// Revised : 9/30/2002
// Version : 0.6
// Target MCU : Atmel AVR Series
// Editor Tabs : 4
//
// NOTE: This code is currently below version 1.0, and therefore is considered
// to be lacking in some functionality or documentation, or may not be fully
// tested. Nonetheless, you can expect most functions to work.
//
// This code is distributed under the GNU Public License
// which can be found at http://www.gnu.org/licenses/gpl.txt
//
//*****************************************************************************
#ifndef WIN32
#include <avr/io.h>
#include <avr/signal.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#endif
#include "global.h"
// include timer support
#ifdef __AVR_ATmega128__
#include "timer128.h"
#else
#include "timer.h"
#endif
// include rtc header
#include "rtc.h"
// Program ROM constants
static char __attribute__ ((progmem)) MonthDayTable[] = {31,28,31,30,31,30,31,31,30,31,30,31};
// Global variables
// time registers
RtcTimeType RtcTime;
void rtcInit(void)
{
// set up timer for RTC operation
// initialize real-time registers
RtcTime.totaltics = 0;
RtcTime.tics = 0;
RtcTime.seconds = 0;
RtcTime.minutes = 0;
RtcTime.hours = 0;
RtcTime.day = 1;
RtcTime.month = 1;
RtcTime.year = 2000;
// select the correct RTC timer based on bit defines
#ifdef AS2
// use timer2 for most AVRs
// initialize timer 2
timer2Init();
// count with 32.768KHz/8
timer2SetPrescaler(TIMER_CLK_DIV8);
// switch to asynchronous input (32KHz crystal)
sbi(ASSR, AS2);
// attach service to real-time clock interrupt
// rtcService() will be called at ((32768/8)/256) = 16Hz
timerAttach(TIMER2OVERFLOW_INT, rtcService);
#else
#ifdef AS0
// use timer0 for ATmega103, ATmega128
// initialize timer 0
timer0Init();
// count with 32.768KHz/8
timer0SetPrescaler(TIMER_CLK_DIV8);
// switch to asynchronous input (32KHz crystal)
sbi(ASSR, AS0);
// attach service to real-time clock interrupt
// rtcService() will be called at ((32768/8)/256) = 16Hz
timerAttach(TIMER0OVERFLOW_INT, rtcService);
#endif
#endif
}
void rtcService(void)
{
// update real-time clock registers
RtcTime.totaltics++;
RtcTime.tics++;
// check for overflows
if(RtcTime.tics == 16) // tics
{
RtcTime.tics = 0;
RtcTime.seconds++; // increment seconds
if(RtcTime.seconds > 59) // check seconds overflow
{
RtcTime.seconds -= 60;
RtcTime.minutes++; // increment minutes
if(RtcTime.minutes > 59) // check minutes overflow
{
RtcTime.minutes -= 60;
RtcTime.hours++; // increment hours
if(RtcTime.hours > 23) // check hours overflow
{
RtcTime.hours -= 24;
RtcTime.day++; // increment days
// check days overflow
if(RtcTime.day == pgm_read_byte(&MonthDayTable[RtcTime.month-1]))
{
RtcTime.day = 1;
RtcTime.month++; // increment months
if(RtcTime.month == 13) // check months overflow
{
RtcTime.month = 1;
RtcTime.year++; // increment years
}
}
}
}
}
}
}
RtcTimeType* rtcGetTime(void)
{
// return the real-time clock data
return &RtcTime;
}