Hello, im wondering if I can use the Vbus line from my usb header to power my ATMEGA2560?
By USB header do you mean a USB breakout that provides +5V (Vbus), D+, D- and GND?
From memory, a lot depends on the USB host. Some limit the current to 100mA and require the USB device to identify itself as a high power device before upping the current to 500mA.
It also depends on what you mean by ATMEGA2560? Are you referring to the chip itself or a MEGA2560 based board?
Yea I meant the USB breakout, and I'm using the ATMEGA2560 chip. I'm using UJ2-BH-1-TH to connect to a CP2102 for usb to serial communication.
That is how the Arduino boards get their power.