Source Code for Module RTC_DS1307

  1  # RTC_DS1307.py 
  2  # Code inspired from GitHub: sorz/DS1307.py 
  3   
  4  import smbus 
  5   
  6 -def bcdToInt(bcd): 
  7      ''' 
  8      Converts byte interpreted as two digit bcd to integer 
  9      (e.g. 88 = b01011000->bcd0101'1000 = 58) 
 10      ''' 
 11      out = 0 
 12      for d in (bcd >> 4, bcd): 
 13          for p in (1, 2, 4 ,8): 
 14              if d & 1: 
 15                  out += p 
 16              d >>= 1 
 17          out *= 10 
 18      return out // 10 
 19   
 20 -def intToBcd(n): 
 21      ''' 
 22      Converts integer 0..99 to byte interpreted in two digit bcd format. 
 23      (e.g. 58 = bcd0101'1000->b01011000 = 88) 
 24      ''' 
 25      bcd = 0 
 26      for i in (n // 10, n % 10): 
 27          for p in (8, 4, 2, 1): 
 28              if i >= p: 
 29                  bcd += 1 
 30                  i -= p 
 31              bcd <<= 1 
 32      return bcd >> 1 
 33   
 34 -class RTC(): 
 35      _REG_SECONDS = 0x00 
 36      _REG_MINUTES = 0x01 
 37      _REG_HOURS = 0x02 
 38      _REG_DOW = 0x03 
 39      _REG_DAY = 0x04 
 40      _REG_MONTH = 0x05 
 41      _REG_YEAR = 0x06 
 42      _REG_CONTROL = 0x07 
 43   
 44 -    def __init__(self, type = 1, addr = 0x68): 
 45          ''' 
 46          Creates a Real Time Clock abstraction using given SMBus type and I2C address 
 47          @param type: 0 for RPi model A, 1 for higher versions (default: 1) 
 48          @param addr: I2C address (default: 0x68) 
 49          ''' 
 50          self._bus = smbus.SMBus(type) 
 51          self._addr = addr 
 52   
 53 -    def _write(self, register, data): 
 54          self._bus.write_byte_data(self._addr, register, data) 
 55   
 56   
 57 -    def _read(self, data): 
 58          returndata = self._bus.read_byte_data(self._addr, data) 
 59          return returndata 
 60   
 61 -    def getSeconds(self): 
 62          ''' 
 63          Returns current seconds. 
 64          @return: seconds of current date/time (0..59) 
 65          ''' 
 66          return bcdToInt(self._read(self._REG_SECONDS)) 
 67   
 68 -    def getMinutes(self): 
 69          ''' 
 70          Returns current minutes. 
 71          @return: minutes of current date/time (0..59) 
 72          ''' 
 73          return bcdToInt(self._read(self._REG_MINUTES)) 
 74   
 75 -    def getHours(self): 
 76          ''' 
 77          Returns current hours. 
 78          @return: hours of current date/time (0..23) 
 79          ''' 
 80          d = self._read(self._REG_HOURS) 
 81          if (d == 0x64): 
 82              d = 0x40 
 83          return bcdToInt(d & 0x3F) 
 84   
 85 -    def getDow(self): 
 86          ''' 
 87          Returns current day of week. 
 88          @return: day number of current date/time (1..7, 1 for Monday) 
 89          ''' 
 90          return bcdToInt(self._read(self._REG_DOW)) 
 91   
 92 -    def getDay(self): 
 93          ''' 
 94          Returns current day of month. 
 95          @return: day of current date/time (1..31) 
 96          ''' 
 97          return bcdToInt(self._read(self._REG_DAY)) 
 98   
 99 -    def getMonth(self): 
100          ''' 
101          Returns current month. 
102          @return: month of current date/time (1..12) 
103          ''' 
104          return bcdToInt(self._read(self._REG_MONTH)) 
105   
106 -    def getYear(self): 
107          ''' 
108          Returns current year. 
109          @return: year of current date/time (0..99) 
110          ''' 
111          return bcdToInt(self._read(self._REG_YEAR)) 
112   
113 -    def setDate(self, seconds = None, minutes = None, hours = None, dow = None, 
114              day = None, month = None, year = None): 
115          ''' 
116          Sets the current date/time. 
117          Range: seconds [0,59], minutes [0,59], hours [0,23], 
118                 day_of_week [1,7], day [1-31], month [1-12], year [0-99]. 
119          If a parameter is None (default), the current value is unchanged 
120          ''' 
121          if seconds is not None: 
122              if seconds < 0 or seconds > 59: 
123                  raise ValueError('Seconds is out of range [0,59].') 
124              self._write(self._REG_SECONDS, intToBcd(seconds)) 
125   
126          if minutes is not None: 
127              if minutes < 0 or minutes > 59: 
128                  raise ValueError('Minutes is out of range [0,59].') 
129              self._write(self._REG_MINUTES, intToBcd(minutes)) 
130   
131          if hours is not None: 
132              if hours < 0 or hours > 23: 
133                  raise ValueError('Hours is out of range [0,23].') 
134              self._write(self._REG_HOURS, intToBcd(hours)) 
135   
136          if year is not None: 
137              if year < 0 or year > 99: 
138                  raise ValueError('Years is out of range [0,99].') 
139              self._write(self._REG_YEAR, intToBcd(year)) 
140   
141          if month is not None: 
142              if month < 1 or month > 12: 
143                  raise ValueError('Month is out of range [1,12].') 
144              self._write(self._REG_MONTH, intToBcd(month)) 
145   
146          if day is not None: 
147              if day < 1 or day > 31: 
148                  raise ValueError('Day is out of range [1,31].') 
149              self._write(self._REG_DAY, intToBcd(day)) 
150   
151          if dow is not None: 
152              if dow < 1 or dow > 7: 
153                  raise ValueError('Day Of Week is out of range [1,7].') 
154              self._write(self._REG_DOW, intToBcd(dow)) 
155   
156 -    def getDate(self): 
157          ''' 
158          Returns the current date/time. 
159          @return: date/time in a tuple with order 
160          (year, month, day, dow, hours, minutes, seconds) 
161          ''' 
162          return (self.getYear(), self.getMonth(), self.getDay(), 
163                  self.getDow(), self.getHours(), self.getMinutes(), 
164                  self.getSeconds()) 
165   
166 -    def getDateStr(self): 
167          ''' 
168          Returns the current date/time. 
169          @return: date/time in a string with format 
170          year-month-day hours:minutes:seconds 
171          ''' 
172          return "20%02d-%02d-%02d %02d:%02d:%02d" %(self.getYear(), self.getMonth(), self.getDay(), self.getHours(), self.getMinutes(), self.getSeconds()) 
173