This is a great battery-backed real time clock (RTC) that allows your microcontroller project to keep track of time even if it is reprogrammed, or if the power is lost. Perfect for datalogging, clock-building, time stamping, timers and alarms, etc. The DS1307 is the most popular RTC - but it requires 5V power to work.
The DS1307 is simple and inexpensive but not a high precision device. It may lose or gain up to two seconds a day. For a high-precision, temperature compensated alternative, please check out the DS3231 precision RTC. If you do not need a DS1307, or you need a 3.3V-power/logic capable RTC please check out our affordable PCF8523 RTC breakout.
This driver depends on:
Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.
Of course, you must import the library to use it:
import busio import adafruit_ds1307 import time
All the Adafruit RTC libraries take an instantiated and active I2C object
busio library) 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:
from board import *
You can also use pins defined by the onboard
microcontroller through the
Now, to initialize the I2C bus:
myI2C = busio.I2C(SCL, SDA)
Once you have created the I2C interface object, you can use it to instantiate the RTC object:
rtc = adafruit_ds1307.DS1307(myI2C)
To set the time, you need to set
datetime to a
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 the
attribute and access the standard attributes of a struct_time such as
t = rtc.datetime print(t) print(t.tm_hour, t.tm_min)
Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.
To build this library locally you’ll need to install the circuitpython-build-tools package.
python3 -m venv .env source .env/bin/activate pip install circuitpython-build-tools
Once installed, make sure you are in the virtual environment:
Then run the build:
circuitpython-build-bundles --filename_prefix adafruit-circuitpython-ds1307 --library_location .
Sphinx is used to build the documentation based on rST files and comments in the code. First, install dependencies (feel free to reuse the virtual environment from above):
python3 -m venv .env source .env/bin/activate pip install Sphinx sphinx-rtd-theme
Now, once you have the virtual environment activated:
cd docs sphinx-build -E -W -b html . _build/html
This will output the documentation to
docs/_build/html. Open the index.html in your browser to
view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to
locally verify it will pass.