Package: adafruit-circuitpython-ds3231
IntroductionThe datasheet for the DS3231 explains that this part is an
“Extremely Accurate I²C-Integrated RTC/TCXO/Crystal”. And,
hey, it does exactly what it says on the tin! This Real Time
Clock (RTC) is the most precise you can get in a small, low
power package.Most RTCs use an external 32kHz timing crystal that is used
to keep time with low current draw. And that’s all well and
good, but those crystals have slight drift, particularly when
the temperature changes (the temperature changes the oscillation
frequency very very very slightly but it does add up!) This
RTC is in a beefy package because the crystal is inside the
chip! And right next to the integrated crystal is a temperature
sensor. That sensor compensates for the frequency changes by
adding or removing clock ticks so that the timekeeping stays
on schedule.This is the finest RTC you can get, and now we have it in a
compact, breadboard-friendly breakout. With a coin cell
plugged into the back, you can get years of precision
timekeeping, even when main power is lost. Great for
datalogging and clocks, or anything where you need to
really know the time.DependenciesThis driver depends on:Adafruit CircuitPythonBus DeviceRegisterPlease ensure all dependencies are available on the CircuitPython filesystem.
This is easily achieved by downloadingthe Adafruit library and driver bundle.Installing from PyPIOn supported GNU/Linux systems like the Raspberry Pi, you can install the driver locallyfrom
PyPI. To install for current user:pip3installadafruit-circuitpython-ds3231To install system-wide (this may be required in some cases):sudopip3installadafruit-circuitpython-ds3231To install in a virtual environment in your current project:mkdirproject-name&&cdproject-namepython3-mvenv.venvsource.venv/bin/activatepip3installadafruit-circuitpython-ds3231Usage NotesBasicsOf course, you must import the library to use it:importadafruit_ds3231importtimeAll the Adafruit RTC libraries take an instantiated and active I2C object
(from theboardlibrary) as an argument to their constructor. The way to
create an I2C object depends on the board you are using. For boards with labeled
SCL and SDA pins, you can:importboardNow, to initialize the I2C bus:i2c=board.I2C()# uses board.SCL and board.SDAOnce you have created the I2C interface object, you can use it to instantiate
the RTC object:rtc=adafruit_ds3231.DS3231(i2c)Date and timeTo set the time, you need to setdatetimeto atime.struct_timeobject:rtc.datetime=time.struct_time((2017,1,9,15,6,0,0,9,-1))After the RTC is set, you retrieve the time by reading thedatetimeattribute and access the standard attributes of a struct_time such astm_year,tm_hourandtm_min.t=rtc.datetimeprint(t)print(t.tm_hour,t.tm_min)AlarmTo set the time, you need to setalarm1oralarm2to a tuple with atime.struct_timeobject and string representing the frequency such as “hourly”:rtc.alarm1=(time.struct_time((2017,1,9,15,6,0,0,9,-1)),"daily")After the RTC is set, you retrieve the alarm status by reading the correspondingalarm1_statusoralarm2_statusattributes. Once True, set it back to False
to reset.ifrtc.alarm1_status:print("wake up!")rtc.alarm1_status=FalseDocumentationAPI documentation for this library can be found onRead the Docs.For information on building library documentation, please check outthis guide.ContributingContributions are welcome! Please read ourCode of Conductbefore contributing to help this project stay welcoming.