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

Created Sun, 08 Sep 2013 06:50:13 +0000 by davervw

davervw

Sun, 08 Sep 2013 06:50:13 +0000

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 [url]http://techwithdave.blogspot.com/2013/09/3v-5v-switchable-i2c-real-time-clock.html[/url]