How do I program setup configuration on Arduino Mega R3 ?

"This setup has other implications. When the Mega2560 is connected to either a computer running Mac OS X or Linux, it resets each time a connection is made to it from software (via USB). For the following half-second or so, the bootloader is running on the Mega2560. While it is programmed to ignore malformed data (i.e. anything besides an upload of new code), it will intercept the first few bytes of data sent to the board after a connection is opened. If a sketch running on the board receives one-time configuration or other data when it first starts, make sure that the software with which it communicates waits a second after opening the connection and before sending this data."

My Arduino Mega R3 does not reset if I connect it to computer. How do I program the setup configuration of the program?

marcopinter999: My Arduino Mega R3 does not reset if I connect it to computer.

My Arduinos reset when connected to a PC when powered by USB and when the PC opens a serial connection to the Arduino.

If your Arduiono does not in both cases, it is probably broken, if it does not reset on a serial connection only, it could be modified not to reset on a serial connection, or broken.

The quoted text describes a scenario where some startup information has to be transferred on startup, do you really want/need such a serial startup setup?

marcopinter999:
My Arduino Mega R3 does not reset if I connect it to computer. How do I program the setup configuration of the program?

How do you know?
Do you have problem uploading sketches?
Has it worked before?
Have you tried it on another computer?
Is it an original or an clone?
Is it detected in Arduino IDE?
Which version of the IDE? Tried another version?
Operating system? If windows, looked for it in device manager for the board?