Colony

/*

time.c

anything that requires a delay

mostly delay_ms

author: Robotics Club, Colony Project

*/

#include <avr/interrupt.h>

#include <util/delay.h>

#include <time.h>

#include <help.h>

#include <serial.h>

static volatile int _rtc_val = 0;

static void (*_rtc_f)(void) = 0;

/*

delay_ms

delays for ms milliseconds

accuracy is unknown (off by tens of nanoseconds every 15 ms)

*/

void delay_ms(int ms) 

{

        for(; ms > 15; ms-=15)

                _delay_ms(15);

        _delay_ms(ms);

}

void pause_ms(int ms)

{

        delay_ms(ms);

}

void pause(int ms)

{

        delay_ms(ms);

}

void sleep_ms(int ms)

{

        delay_ms(ms);

}

void sleep(int ms)

{

        delay_ms(ms);

}

/*

void rtc_init(void)

call this function to start the real time timer

use rtc() to get the time value and rtc_resest() to reset

requires global interrupts to be enabled for proper use

(I bit of SREG register should be set)

uses TIMER0 on asynchronous mode

*/

void rtc_init(int prescale_opt, unsigned char ocr_val, void (*rtc_func)(void)){

        int mask = _BV(TCN0UB) + _BV(OCR0UB) + _BV(TCR0UB);

        char tmp;

        TIMSK &= ~(_BV(OCIE0) + _BV(TOIE0)); //1. disable interrupts

        ASSR |= _BV(AS0); //2. selecting clock source (external)

        //3. writing new values to TCCR, TCNT, OCR

        TCNT0 = 0;

        OCR0 = ocr_val;

        TCCR0 = (0x01 << 3) + (prescale_opt & 0x07); //setting CTC mode, prescaler is lowest 3 bits

        //4. waiting for busy bits to clear

        tmp = ASSR;

        while( tmp & mask ){

                tmp = ASSR;

        }

        TIFR &= ~(_BV(OCF0) + _BV(TOV0)); //5. clearing the interrupt flags

        TIMSK |= _BV(OCIE0); // + _BV(TOIE0); //6. enabling interrupts

        _rtc_f = rtc_func;

}

int rtc(void){

        return _rtc_val;

}

void rtc_reset(void){

        _rtc_val = 0;

}

SIGNAL (SIG_OUTPUT_COMPARE0){

        _rtc_val++;

        if(_rtc_f != 0)

                _rtc_f();

}