3V-5V Switchable I2C Real Time Clock (DS1307) Shield

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davervw
Posts: 17
Joined: Sun Jul 31, 2011 5:33 pm

3V-5V Switchable I2C Real Time Clock (DS1307) Shield

Post by davervw » Sun Sep 08, 2013 7:50 am

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Using the Maxim/Dallas 1307 RTC that runs at 5V shown with the Arduino Due that runs at 3V. Also tested with chipKIT Uno32 and Max32 running at 3V, though they are usually 5V tolerant, so while this circuit may be overkill for chipKIT, it is good for a cross-compatible shield. FETs are used for bidirectional level shifter per a Philips app note.

*note: Max32 required separate jumpers to 20/21

More details including schematics here http://techwithdave.blogspot.com/2013/0 ... clock.html

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