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/*
ds1338.c
DS1338 / DS1307 I2C clock module driver
Copyright 2012, 2014 Doug Szumski <d.s.szumski@gmail.com>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>
*/
#include <stdint.h>
#include "ds1338.h"
#include "i2cmaster.h"
static void
ds1338_write(const uint8_t reg, const uint8_t data)
{
i2c_start(DS1338_TWI_ADR + I2C_WRITE);
i2c_write(reg);
i2c_write(data);
i2c_stop();
}
static uint8_t
ds1338_read(const uint8_t reg)
{
i2c_start(DS1338_TWI_ADR + I2C_WRITE);
i2c_write(reg);
i2c_rep_start(DS1338_TWI_ADR + I2C_READ);
uint8_t data = i2c_readNak();
i2c_stop();
return data;
}
void
ds1338_init(void)
{
ds1338_write(DS1338_CONTROL, DS1338_CONTROL_SETTING);
// Set the CS bit to zero to enable clock
uint8_t data = ds1338_read(DS1338_SECONDS);
data &= ~(1 << DS1338_CH);
ds1338_write(DS1338_SECONDS, data);
}
void
ds1338_get_time(ds1338_time_t * const time)
{
uint8_t data = ds1338_read(DS1338_SECONDS);
time->seconds = 10 * ((data & 0b01110000) >> 4) + (data & 0x0F);
data = ds1338_read(DS1338_MINUTES);
time->minutes = UNPACK_BCD(data);
data = ds1338_read(DS1338_HOURS);
if (data & (1 << DS1338_12_24_HR))
{
// 12 hour mode
time->hours = 10 * ((data & 0b00010000) >> 4) + (data & 0x0F);
time->is_pm = data & (1 << DS1338_AM_PM);
} else {
// 24 hour mode
time->hours = 10 * ((data & 0b00110000) >> 4) + (data & 0x0F);
}
data = ds1338_read(DS1338_DAY);
// Shift day so that it's 0-6, not 1-7
time->day = data - 1;
data = ds1338_read(DS1338_DATE);
time->date = UNPACK_BCD(data);
data = ds1338_read(DS1338_MONTH);
time->month = UNPACK_BCD(data);
data = ds1338_read(DS1338_YEAR);
time->year = UNPACK_BCD(data);
}
void
ds1338_set_time(const ds1338_time_t * const time)
{
// Should always write zero to the CS bit to enable the clock
ds1338_write(DS1338_SECONDS, TO_BCD(time->seconds));
ds1338_write(DS1338_MINUTES, TO_BCD(time->minutes));
uint8_t hour_reg = ds1338_read(DS1338_HOURS);
// Wipe everything apart from the 12/24 hour bit
hour_reg &= ~(0b00111111);
if ((hour_reg & (1 << DS1338_12_24_HR)) && (time->is_pm)) {
// 12 hour mode and it's PM
hour_reg |= (1 << DS1338_AM_PM);
}
hour_reg |= TO_BCD(time->hours);
ds1338_write(DS1338_HOURS, hour_reg);
// Shift back day from 0-6 to 1-7.
ds1338_write(DS1338_DAY, time->day + 1);
ds1338_write(DS1338_DATE, TO_BCD(time->date));
ds1338_write(DS1338_MONTH, TO_BCD(time->month));
ds1338_write(DS1338_YEAR, TO_BCD(time->year));
}
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