""" MicroPython TinyRTC I2C Module, DS1307 RTC + AT24C32N EEPROM https://github.com/mcauser/micropython-tinyrtc-i2c MIT License Copyright (c) 2018 Mike Causer 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. BCD Format: https://en.wikipedia.org/wiki/Binary-coded_decimal """ 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]))