Mega2560 R3 Pins 0 & 1

I apologize if this question has been asked and answered, i couldn't find it.

It appears that pins 0&1 are used by the Mega2560 to communicate with the 16U2 USB interface.

I tried testing this by connecting an LED to each pin 0 & 1 with a 1K resistor to ground, and I was unable to load code, so I assume these pins cannot be used.

Is that correct or am i missing something obvious?

Thank you

You are correct. Those data pins double as a hardware serial port connected to the USB-to-Serial chip. They are connected through resistors so you should be able to use them for digital I/O as long as you don't need the Serial port. If you connect them for digital I/O you may have to remove those connections to use them for sketch uploads.

JerryL:
I apologize if this question has been asked and answered, i couldn’t find it.

It appears that pins 0&1 are used by the Mega2560 to communicate with the 16U2 USB interface.

Yes, and therefore the labelling of the pins is RX0 and TX0 besides of 0 and 1.
These two are the pins for “Serial”.