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Author Topic: External AREF with DUE  (Read 877 times)
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I would like to use an external 3.0V reference for A/D conversions.
Looking into the schematics, the related pin on the SAM3X8EA is connected to a (filtered) 3.3V supply. The AREF pin in the standard version of the board (mine is R3) is therefore simply a 3.3V output.
On the other hand, the board seems to have a provision to make a simple change to allow to use the AREF as an input to the SAM3X8EA. There is a small white rectangle drawn on the upper side of the board, with the text "3.3/Ext" above and "AREF" on the right of it, nearby to the ICSP connector.
Can anybody tell me what change has to be made?
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White River Junction, Vermont USA
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From looking at the schematic, you would remove the small 0-ohm jumper located at the "3.3" section of the "AREF" component, and move it to the "EXT" section.

You could then apply your new AvRef input to the AREF-pin on the PWMH header (the header with Pin13 and SDA1).

I like my schematic representation better than what's on the Arduino DUE page.  I added a bit in the upper left to describe this (see PDF here):
http://arduino.cc/forum/index.php/topic,146574.0.html

-Chris
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