from micropython import const DATETIME_REG = const(0) # 0x00-0x06 CHIP_HALT = const(128) CONTROL_REG = const(7) # 0x07 RAM_REG = const(8) # 0x08-0x3F class DS1307(object): """Driver for the DS1307 RTC.""" def __init__(self, i2c, addr=0x68): self.i2c = i2c self.addr = addr self.weekday_start = 1 self._halt = False def _dec2bcd(self, value): """Convert decimal to binary coded decimal (BCD) format""" return (value // 10) << 4 | (value % 10) def _bcd2dec(self, value): """Convert binary coded decimal (BCD) format to decimal""" return ((value >> 4) * 10) + (value & 0x0F) def datetime(self, datetime=None): """Get or set datetime""" if datetime is None: buf = self.i2c.readfrom_mem(self.addr, DATETIME_REG, 7) return ( self._bcd2dec(buf[6]) + 2000, # year self._bcd2dec(buf[5]), # month self._bcd2dec(buf[4]), # day self._bcd2dec(buf[3] - self.weekday_start), # weekday self._bcd2dec(buf[2]), # hour self._bcd2dec(buf[1]), # minute self._bcd2dec(buf[0] & 0x7F), # second 0 # subseconds ) buf = bytearray(7) buf[0] = self._dec2bcd(datetime[6]) & 0x7F # second, msb = CH, 1=halt, 0=go buf[1] = self._dec2bcd(datetime[5]) # minute buf[2] = self._dec2bcd(datetime[4]) # hour buf[3] = self._dec2bcd(datetime[3] + self.weekday_start) # weekday buf[4] = self._dec2bcd(datetime[2]) # day buf[5] = self._dec2bcd(datetime[1]) # month buf[6] = self._dec2bcd(datetime[0] - 2000) # year if (self._halt): buf[0] |= (1 << 7) self.i2c.writeto_mem(self.addr, DATETIME_REG, buf) def halt(self, val=None): """Power up, power down or check status""" if val is None: return self._halt reg = self.i2c.readfrom_mem(self.addr, DATETIME_REG, 1)[0] if val: reg |= CHIP_HALT else: reg &= ~CHIP_HALT self._halt = bool(val) self.i2c.writeto_mem(self.addr, DATETIME_REG, bytearray([reg])) def square_wave(self, sqw=0, out=0): """Output square wave on pin SQ at 1Hz, 4.096kHz, 8.192kHz or 32.768kHz, or disable the oscillator and output logic level high/low.""" rs0 = 1 if sqw == 4 or sqw == 32 else 0 rs1 = 1 if sqw == 8 or sqw == 32 else 0 out = 1 if out > 0 else 0 sqw = 1 if sqw > 0 else 0 reg = rs0 | rs1 << 1 | sqw << 4 | out << 7 self.i2c.writeto_mem(self.addr, CONTROL_REG, bytearray([reg]))