Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/adafruit/adafruit_circuitpython_pcf8523

Adafruit CircuitPython drivers for the PCF8523 realtime clock.
https://github.com/adafruit/adafruit_circuitpython_pcf8523

circuitpython hacktoberfest

Last synced: 3 months ago
JSON representation

Adafruit CircuitPython drivers for the PCF8523 realtime clock.

Awesome Lists containing this project

README 

        

Introduction to Adafruit's PCF8523 Real Time Clock (RTC) Library

================================================================



.. image:: https://readthedocs.org/projects/adafruit-circuitpython-pcf8523/badge/?version=latest

    :target: https://docs.circuitpython.org/projects/pcf8523/en/latest/

    :alt: Documentation Status



.. image:: https://raw.githubusercontent.com/adafruit/Adafruit_CircuitPython_Bundle/main/badges/adafruit_discord.svg

    :target: https://adafru.it/discord

    :alt: Discord



.. image:: https://github.com/adafruit/Adafruit_CircuitPython_PCF8523/workflows/Build%20CI/badge.svg

    :target: https://github.com/adafruit/Adafruit_CircuitPython_PCF8523/actions/

    :alt: Build Status



.. image:: https://img.shields.io/badge/code%20style-black-000000.svg

    :target: https://github.com/psf/black

    :alt: Code Style: Black



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. Equipped with PCF8523 RTC - it can

run from 3.3V or 5V power & logic!



The PCF8523 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 need a DS1307 for compatibility reasons, check out our

`DS1307 RTC breakout `_.



.. image:: _static/3295-00.jpg

    :alt: PCF8523 Breakout Board



Dependencies

=============



This driver depends on the `Register `_

and `Bus Device `_

libraries. Please ensure they are also available on the CircuitPython filesystem.

This is easily achieved by downloading

`a library and driver bundle `_.



Installing from PyPI

====================

On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally `from

PyPI `_. To install for current user:



.. code-block:: shell



    pip3 install adafruit-circuitpython-pcf8523



To install system-wide (this may be required in some cases):



.. code-block:: shell



    sudo pip3 install adafruit-circuitpython-pcf8523



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-pcf8523



Usage Notes

===========



Basics

------



Of course, you must import the library to use it:



.. code:: python3



    import time

    from adafruit_pcf8523.pcf8523 import PCF8523



All the Adafruit RTC libraries take an instantiated and active I2C object

(from the `board` 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:: python3



    import board



Now, to initialize the I2C bus:



.. code:: python3



    i2c = board.I2C()



Once you have created the I2C interface object, you can use it to instantiate

the RTC object:



.. code:: python3



    rtc = PCF8523(i2c)



Date and time

-------------



To set the time, you need to set datetime` to a `time.struct_time` object:



.. code:: python3



    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:: python3



    t = rtc.datetime

    print(t)

    print(t.tm_hour, t.tm_min)



Alarm

-----



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:: python3



    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:: python3



    if rtc.alarm_status:

        print("wake up!")

        rtc.alarm_status = False



Documentation

=============



API documentation for this library can be found on `Read the Docs `_.



For information on building library documentation, please check out `this guide `_.



Contributing

============



Contributions are welcome! Please read our `Code of Conduct

`_

before contributing to help this project stay welcoming.