I've seen that an ATmega8U2 is used in the Arduino uno board as USB to serial converter. Why we don't burn the ISP function in it?
We could use the B1 to B3 pins for make an ISP bus (the connector is yet availlable). This function could be used for burn the bootloader in a new AVR device or program other AVR devices.
Great idea, mimmo. This approach is not only save bootloader space and but also fast flashing speed then plus save rs232 communication and save Tx, Rx pins if we don't use it too. I love Arduino because of these essential features:
1) No need external power (via USB)
2) No need external components for rs232 communication via PC
3) No need to press reset button after flashing in some cases
4) No need external programmer
But the question is that is it possible to use ATmega8U2 as both ISP programmer and rs232 comm? If we use ATmega8U2 as ISP programmer, it would be great if we put series resistors between ISP lines of both MCU like Buttload ISP of AVR Buttery http://www.fourwalledcubicle.com/ButtLoad.php