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Adafruit PCF8523 Real Time Clock
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Adafruit PCF8523 Real Time Clock

by RobMohr on Sat Sep 21, 2019 10:03 pm

I wish to use the Adafruit PCF8523 module to generate an interrupt that I will be using to wake up the Arduino Due. None of the examples included in the Adafruit RTClib library go over usage of the SQW pin to perform any functionally. It is unclear from the API ( ... ee683f0e63) whether this is supported or not.

There are enum parameters defined for setting the square wave output to fixed values:

Pcf8523SqwPinMode {
PCF8523_OFF = 7, PCF8523_SquareWave1HZ = 6, PCF8523_SquareWave32HZ = 5, PCF8523_SquareWave1kHz = 4,
PCF8523_SquareWave4kHz = 3, PCF8523_SquareWave8kHz = 2, PCF8523_SquareWave16kHz = 1, PCF8523_SquareWave32kHz = 0

But there is no mention in the API of setting alarm values based on either an interval, time of day, date, etc. Could someone comment on the capability of this breakout board to support use of the SQW pin specifically for generating an interrupt at a given time interval, such as 10 minutes?

If possible, and example sketch would be great.

P.S. I assume that SQL will need to be pulled high through a 10K resistor in order to interrupt on the Due digital pin 2?

Thanks for any advice!

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Joined: Tue Jun 12, 2018 8:20 pm

Please be positive and constructive with your questions and comments.