After the introductory post about AREF earlier this month, we've found another interesting tutorial by Telford Dorr. He takes the subject further by demonstrating how to create a more precise voltage reference with a TL431 shunt regulator to create the required reference voltage, whose output is fed through an op-amp which is used to protect the input on the microcontroller if you accidentally misuse the AREF functions in your sketch.
In his own words:
Should the AVCC switch accidentally close, the Aref pin will be pulled up to AVCC, the op amp output will swing to its negative rail (assumed to be 0 vdc here), and the 4.7k resistor will limit the current to little over a milliamp, saving the processor from destruction.
It's a useful yet simple form of increasing accuracy and protection for your Arduino's analogue work, so to learn more visit Telford's tutorial page. And for more, we're on twitter and Google+, so follow us for news and product updates as well.
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