DS3231.py

'''
MIT License

Copyright (c) 2018 bhagyarsh dhumal

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
'''

import datetime
import smbus
from time import  strftime

def _bcd_to_int(bcd):
    """Decode a 2x4bit BCD to a integer.
    """
    out = 0 
    for d in (bcd >> 4, bcd):
        for p in (1, 2, 4 ,8):
            if d & 1:
                out += p
            d >>= 1
        out *= 10
    return int(out / 10)


def _int_to_bcd(n):
    """Encode a one or two digits number to the BCD.
    """
    bcd = 0
    for i in (n // 10, n % 10):
        for p in (8, 4, 2, 1):
            if i >= p:
                bcd += 1
                i -= p
            bcd <<= 1
    return bcd >> 1
class DS3231:
    w  = ["Mon","Tues","Wed","Thur","Fri","Sat","Sun"]
    def __init__(self, twi ,address=0x68, register=0x00):
        self.address = address
        self.register = register
        self._bus = smbus.SMBus(twi) 
        self._datetimelist = []
        self.rtctime = []

   
    def _ds3231SetTime(self,NowTime):
        self._bus.write_i2c_block_data(self.address,self.register,NowTime)
    #/dev/i2c-1
    def _ds3231ReadTime(self):
        return self._bus.read_i2c_block_data(self.address,self.register,7)
# sec min hour week day month year


    def setTime(self,seconds=None, minutes=None, hours=None, weekday =None ,
            date=None, month=None, year=None):

        #    seconds
        if seconds <60 and seconds >= 0:
            self._datetimelist.append(_int_to_bcd(seconds))
        else:
            _datetimelist = []
            raise ValueError('Seconds is out of range [0,59].')   
        #    minutes  
        if minutes <60 and minutes >= 0:
            self._datetimelist.append(_int_to_bcd(minutes))
        else:
            self._datetimelist = []
            raise ValueError('Minutes is out of range [0,59].')   

        #    hours
        if hours <24 and hours >= 0:
            self._datetimelist.append(_int_to_bcd(hours))
        else:
            self._datetimelist = []
            raise ValueError('Hours is out of range [0,23].')  
        #    weekday
        if weekday <7 and weekday >= 0:
            self._datetimelist.append(_int_to_bcd(weekday))
        else:
            self._datetimelist = []
            raise ValueError('weekday is out of range [1,7].')  
        #   day
        if date <=31 and date >= 1:
            self._datetimelist.append(_int_to_bcd(date))
        else:
            self._datetimelist = []
            raise ValueError('date is out of range [1,31].')    
        #   month
        if hours <24 and hours >= 0:
            self._datetimelist.append(_int_to_bcd(hours))
        else:
            self._datetimelist = []
            raise ValueError('month is out of range [1,12].')             
         #  year

        if year <100 and year >= 0:
            self._datetimelist.append(_int_to_bcd(year))
        else:
            self._datetimelist = []
            raise ValueError('year is out of range [0,99].') 

        self._ds3231SetTime(self._datetimelist)


    def setNow(self):
        t =  datetime.datetime.now()
        week = datetime.datetime.today().weekday()
        sec = int(t.strftime("%S"))
        min = int(t.strftime("%M"))
        hour = int(t.strftime("%H"))
        day = int(t.strftime("%d"))
        month = int(t.strftime("%m"))
        year = int(t.strftime("%Y")[2:])
        print(year)
        NowTime = [_int_to_bcd(sec),_int_to_bcd(min),_int_to_bcd(hour)
                ,_int_to_bcd(week),_int_to_bcd(day),_int_to_bcd(month),_int_to_bcd(year)]
        self._bus.write_i2c_block_data(self.address,self.register,NowTime)
    def readTime(self):
        t = self._ds3231ReadTime()
        sec = _bcd_to_int(t[0])
        min = _bcd_to_int(t[1])
        hour = _bcd_to_int(t[2])
        day = _bcd_to_int(t[4])
        month = _bcd_to_int(t[5])
        year = _bcd_to_int(t[6])
        time = datetime.datetime(year=year,month=month,day=day,hour=hour,minute=min,second=sec)
        print(time)
        return time
if __name__ == "__main__":
    dt = DS3231(0)
    dt.readTime()