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arduino / ArduinoCore-samd

Arduino Core for SAMD21 CPU
GNU Lesser General Public License v2.1
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SAM D21 on MKR Zero doesn't work with DS3231 RTC #396

Open Bushedo opened 5 years ago

Bushedo commented 5 years ago

Have been trying to integrate DS3231 RTC to work with MKR Zero through the I2C bus without success. Other units on the bus like a BME280 work, and when scanned, the board returns the address of the RTC and its on board memory chip. Used several DS3231 libraries including RTClib but none seem to work. After changing the date and time in the code using the example code from the library, the unit always returns the same date 2 Feb 2019 (yes, USA groundhog day!). The clock module works great with an Uno. Suspect it could be a timing issue, but can't see any obvious suspects in the library source code.

agdl commented 5 years ago

Are you sure the module you are using can be supplied at 3.3V?

Bushedo commented 5 years ago

The RTC is HiLetgo DS3231 AT24C32. Seller says it operates from 3.3-5v. When it is operating with the Uno I’m supplying 3.3V to the module. The Uno is running on the 5v from the USB cable. The grounds are tied together.

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From: Arturo Guadalupi notifications@github.com Sent: Friday, March 29, 2019 10:38:32 AM To: arduino/ArduinoCore-samd Cc: Bushedo; Author Subject: Re: [arduino/ArduinoCore-samd] SAM D21 on MKR Zero doesn't work with DS3231 RTC (#396)

Are you sure the module you are using can be supplied at 3.3V?

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agdl commented 5 years ago

If you supply it at 3.3V and using an uno you are using anyways GPIOS on the uno at 5V. So you are stressing the component a lot to use clamping diodes. on the uno you should suply it at 5V

Bushedo commented 5 years ago

The only reason I was using the Uno was to test the module. Thought the test would be more realistic if I used the same voltage as the MKR Zero.