Voltage Max on ATMEGA328 Analog Inputs?

Question

Does anyone know what the max voltage that can be applied to the analog inputs of the ATMEGA328 Arduino uP? I know that it will convert 0V to 5V but how much tolerance does it have for voltages over 5 volts?

Thanks

John

mcb1 · Accepted Answer

From the Atmega328 manual Mark

Problemchild · Answer

Amazed at the high voltage capability on the Reset...obviously expecting abuse there!

One thing to note is that your signal doesn't have any transients otherwise you'll need to take those in to account as your maximum values.

shabaz · Answer

Hi John! That may be some old-school Flash mem programming voltage pin for non-in-circuit programming. Not sure, I didn't check the datasheet, but I recall a load of Flash devices requiring 12V.

jadew · Answer

It's used for high voltage programming. That way, even if you disable the reset pin (via programmable fuses), you can still re-flash it/reset the fuses.

Problemchild · Answer

O yeah probably ...right voltage too. The 328 seems to stand a fair amount of abuse!

dougw · Answer

It sounds like if the external circuit has a high enough output impedance the protection diodes will clamp the voltage to safe levels. I would look how much current the protection diodes can handle, but I can't even handle PDFs out here in the boonies.

Problemchild · Answer

Otherthing to note is that values over the maximum will be converted as the maximum value and the same for the minimum so inputs beyond the GND-VCC will be clipped. Some signal conditioning on your part would be required.

Good luck

Voltage Max on ATMEGA328 Analog Inputs?

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