Adafruit CircuitPython drivers for the PCF8563 realtime clock.
MIT License
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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 PCF8563 is simple and inexpensive but not a high precision device.
It may lose or gain multiple seconds a day. For a high-precision,
temperature compensated alternative, please check out the
DS3231 precision RTC. <https://www.adafruit.com/products/3013>
_
If you need a DS1307 for compatibility reasons, check out our
DS1307 RTC breakout <https://www.adafruit.com/products/3296>
_.
This driver depends on the Register <https://github.com/adafruit/Adafruit_CircuitPython_Register>
_
and Bus Device <https://github.com/adafruit/Adafruit_CircuitPython_BusDevice>
_
libraries. Please ensure they are also available on the CircuitPython filesystem.
This is easily achieved by downloading
a library and driver bundle <https://github.com/adafruit/Adafruit_CircuitPython_Bundle>
_.
On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI <https://pypi.org/project/adafruit-circuitpython-pcf8563/>
_. To install for current user:
.. code-block:: shell
pip3 install adafruit-circuitpython-pcf8563
To install system-wide (this may be required in some cases):
.. code-block:: shell
sudo pip3 install adafruit-circuitpython-pcf8563
To install in a virtual environment in your current project:
.. code-block:: shell
mkdir project-name && cd project-name
python3 -m venv .venv
source .venv/bin/activate
pip3 install adafruit-circuitpython-pcf8563
Of course, you must import the library to use it:
.. code:: python
import busio
from adafruit_pcf8563.pcf8563 import PCF8563
import time
All the Adafruit RTC libraries take an instantiated and active I2C object
(from the 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:
.. code:: python
from board import *
Now, to initialize the I2C bus:
.. code:: python
i2c_bus = board.I2C()
Once you have created the I2C interface object, you can use it to instantiate the RTC object:
.. code:: python
rtc = PCF8563(i2c_bus)
To set the time, you need to set datetime
to a time.struct_time
object:
.. code:: python
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 datetime
attribute and access the standard attributes of a struct_time such as tm_year
,
tm_hour
and tm_min
.
.. code:: python
t = rtc.datetime
print(t)
print(t.tm_hour, t.tm_min)
To set the time, you need to set alarm
to a tuple with a time.struct_time
object and string representing the frequency such as "hourly":
.. code:: python
rtc.alarm = (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
alarm_status
attribute. Once True, set it back to False to reset.
.. code:: python
if rtc.alarm_status:
print("wake up!")
rtc.alarm_status = False
API documentation for this library can be found on Read the Docs <https://docs.circuitpython.org/projects/pcf8563/en/latest/>
_.
For information on building library documentation, please check out this guide <https://learn.adafruit.com/creating-and-sharing-a-circuitpython-library/sharing-our-docs-on-readthedocs#sphinx-5-1>
_.
Contributions are welcome! Please read our Code of Conduct <https://github.com/adafruit/Adafruit_CircuitPython_PCF8563/blob/master/CODE_OF_CONDUCT.md>
_
before contributing to help this project stay welcoming.