For a project I am programming an Atmega 328 AU on a custom made PCB. After a lot of struggles I managed to get a bootloader and a program on the chip. I programmed some IO pins and they seem to work fine. The output pins that I use give: LOW = 0 Volt High = 5 Volt which is desired. However, one pin, pin 9 of the chip, gives: LOW = 0 Volt, HIGH = 1 Volt. The 1 Volt does not trigger my opto-coupler so I would like this pin also to give HIGH = 5 Volt. Is there any way to change this in software?
I use the Arduino IDE for programming.
Thank you guys.
edit: Still not figured out. Ill add some schematics. Note: The supply is not that flat with my own power supply, but I could add a bigger capacitor. However, for the opto-coupler is does not matter and the output will correctly trigger the opto-coupler for the 5V.