i can use the Arduino IDE to compile my program into hex code right?
Maybe you can write a batch file that runs the AVRdude commands that the IDE runs.Still requires customers to have avrdude, or some portion of it, on the PC.
Yes but AVRdude is for In system programming right?
In system programming requires the users to have an AVR ISP to connect to the ICSP header on the board. Serial just requires them to connect PC USB to USB/Serial on your board as PaulS said.
Isn't there some back & forth comm's as part of the programming? So the PC side needs some smarts to receive data from the bootloader running on the 328 and decide if things are working.
Isn't there some back & forth comm's as part of the programming?