Hi guys
I have Arduino Mega 2560, my board was working properly but since last week analog input A0 works properly and other analog inputs (A1, A2, A3,..) do not work (i mean the int number doesn't change),
i wrote a sketch to read all analog values and then found out that A0 affects all other analog inputs ,
pls help me !!!
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The analog inputs are somehow connected internally via a seperate power supply for the analog inputs.
So if you supply a voltage that is above 5V or below 0V, the other analog inputs can do strange things.
Or if there is a problem with AVcc (the power supply to the ATmega2560 chip for analog inputs), you can have this.
Perhaps your Arduino Mega 2560 is broken or badly soldered.
Can you tell us what kind of analog signals you supplied to the analog inputs ? More than 5V ?
tnx dear friend for your reply
I do not remember if I supplied voltage more than 5 V but maybe i supplied below 0,
anyway I mentioned that A0 works properly and read analog voltage perfectly, but other analog inputs (A1,A2,...)
dont work at all,
when i supply voltage (0-5) to other analog inputs nothing happens,
why ??
thank you in advance
You somehow managed to ruin all of the analog inputs, except the one that still works.
If you supply a negative voltage, it may only be 1mA.
You can use protection resistors. For example resistors of 1k to 10k for the input pins.
when i supply voltage (0-5) to other analog inputs nothing happens, why ??
Yes my vote is for you have blown them up as well.
If they did work at one time but now don't it sounds like you have damaged them.
i wrote a sketch to read all analog values and then found out that A0 affects all other analog inputs
That sounds like you have damaged the analogue multiplexer part of the chip.
thank all you guys ,
Finally i found the problem which ws on sketch side,