Hi everyone, I currently have an Arduino code project based on the Nano which I'm programming to a standalone ATMega 328P on a custom board of mine. Since my project doesn't require serial communication, I'm using the TX/RX ports as general I/O. The only issue is that the TX/RX pins respectively are being held at Vcc and Gnd, despite setting them as outputs. You can watch the voltage dip/rise by a few hundred milivolts when trying to toggle the output state on them, but they stay fairly constant.
After several hours of head scratching and questioning my layout/swapping IC's and components, I decided to create a piece of test code in Atmel AVR to set what are normally TX/RX on Arduino boards as general purpose outputs and toggle them high and low which worked perfectly fine.
Therefore, it seems the Arduino compiler is doing something weird with those two pins, like defaulting to a serial enabled state possibly? I'm wondering how to prevent it from doing this so I can use those pins as I/O.
Thanks in advance.