rtc.c

#include "rtc.h"

#include <avr/pgmspace.h>
#include "i2c.h"

RTC_type rtc;

const static RTC_type rtcMin PROGMEM = {0, 0, 0, 1, 1, 1, 1, RTC_NOEDIT};
const static RTC_type rtcMax PROGMEM = {59, 59, 23, 7, 31, 12, 99, RTC_NOEDIT};

static void rtcWeekDay(void)
{
	uint8_t a, y, m;

	a = (rtc.month > 2 ? 0 : 1);
	y = 12 + rtc.year - a;
	m = rtc.month + 12 * a - 2;

	rtc.wday = (rtc.date + y + (y / 4) + ((31 * m) / 12)) % 7;
	if (rtc.wday == 0)
		rtc.wday = 7;

	return;
}

static uint8_t rtcDaysInMonth(void)
{
	uint8_t ret = rtc.month;

	if (ret == 2) {
		ret = rtc.year & 0x03;
		ret = (ret ? 29 : 28);
	} else {
		if (ret > 7)
			ret++;
		ret |= 30;
	}

	return ret;
}

void rtcReadTime(void)
{
	uint8_t temp;
	uint8_t i;

	I2CStart(RTC_I2C_ADDR);
	I2CWriteByte(RTC_SEC);
	I2CStart(RTC_I2C_ADDR | I2C_READ);
	for (i = RTC_SEC; i <= RTC_YEAR; i++) {
		temp = I2CReadByte((i == RTC_YEAR) ? I2C_NOACK : I2C_ACK);
		*((int8_t*)&rtc + i) = rtcBinDecToDec(temp);
	}
	I2CStop();

	return;
}

static void rtcSaveTime(void)
{
	uint8_t i;
	uint8_t etm = rtc.etm;

	if (etm > RTC_WDAY) {
		rtcWeekDay();
		etm = RTC_WDAY;
	}

	I2CStart(RTC_I2C_ADDR);
	I2CWriteByte(etm);
	if (etm == RTC_SEC) {
		I2CWriteByte(0);
	} else {
		for (i = etm; i <= RTC_YEAR; i++)
			I2CWriteByte(rtcDecToBinDec(*((int8_t*)&rtc + i)));
	}

	I2CStop();

	return;
}

void rtcNextEditParam(void)
{
	switch (rtc.etm) {
	case RTC_HOUR:
	case RTC_MIN:
		rtc.etm--;
		break;
	case RTC_SEC:
		rtc.etm = RTC_DATE;
		break;
	case RTC_DATE:
	case RTC_MONTH:
		rtc.etm++;
		break;
	default:
		rtc.etm = RTC_HOUR;
		break;
	}

	return;
}

void rtcChangeTime(int8_t diff)
{
	int8_t *time = (int8_t*)&rtc + rtc.etm;
	int8_t timeMax = pgm_read_byte((int8_t*)&rtcMax + rtc.etm);
	int8_t timeMin = pgm_read_byte((int8_t*)&rtcMin + rtc.etm);

	if (rtc.etm == RTC_DATE)
		timeMax = rtcDaysInMonth();

	*time += diff;

	if (*time > timeMax)
		*time = timeMin;
	if (*time < timeMin)
		*time = timeMax;

	rtcSaveTime();

	return;
}


uint8_t rtcBinDecToDec(uint8_t num)
{
	return (num >> 4) * 10 + (num & 0x0F);
}


uint8_t rtcDecToBinDec(uint8_t num)
{
	return ((num / 10) << 4) + (num % 10);
}