parasitic voltage at the analog pin terminal of my atmega328

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1

Hello everyone,

I'm working on a project to make my own Arduino board with some customization and today I'm facing a problem after I realized my card I checked is there is no short circuit and when I feed the card without putting the microcontroller I have 0v in the analog input of the microcontroller but when I plug the micro controller, I have a voltage of 1.6v in the analog input, I put a capacitor 100n to the terminal of the AREF input and the ground but it did not change anything! I show you my diagram which for me is correct but I really can not find where it comes from!
i have bootloaded atmega328p-pu
i dont no if there is somthing to to resolve this becais all other digital input working !

schematic.pdf (114 KB)

EOSMART-PCB-TT.pdf (61.7 KB)

2

didouh_j:
I have a voltage of 1.6v in the analog input,

What this mean? How you measure the voltage and where? If the pin is floating (not connected to anything) nearly any voltage can be on the pin. If you are sampling more analog pins and have high impedance input the sample and hold capacitor inside ATMega will "move" charge between pins.