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Topic: I think I might have broken the External Referance Arduino Mega (Read 1 time) previous topic - next topic


Jun 22, 2012, 03:36 pm Last Edit: Jun 22, 2012, 03:40 pm by michaud85 Reason: 1
Hey guys, I turned on my power supply this morning and for some reason it was set to 17 v I only had it on for a few seconds but now I dont think the external reference is working. it could be a problem with my circuit but I am just wondering if i possibly friend the Aref pin. Also even if I did ruin the Aref pin will the internal referances still have functionality?

Also about 16V went into the A0 pin. COuld that be damaged too? Only 3mA of current was going through the circuit.


More than likely you fried the 2 pins,and possibly pins near them. They can only take an absolute max of 6V.
If the chip feels hot when you power up then you've damaged it.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Tom Carpenter

Depending on how much damage you did, it is concievable the internal reference might work. However there is only one ADC in the atmega chip, and all the analog pins are connected to it via a built in multiplexer. It is possible you could have damage the Mux, in which case probably none of the analog pins will ever work again.

Try one of the analog examples with a resistor divider or potentiometer on one of the analog pins, and see if the ADC reads a sensible value.

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