Can I take out the Atmage328 and replace with a Atega8 for programing instead of trying to program using a breadboard?
Atmega8 has a smaller memory but should be a pin-compatible replacement to the Atmega328 for most purposes. Note, however, that the Atmega8 does have a smaller memory, and also a few registers are different, so some might not work, but most common ones should work just fine.
In terms of the Arduino environment, you'll need to do two things:
- First burn the corresponding Arduino bootloader (the one named "Arduino NG or older w/ ATmega8" in the Arduino IDE) onto your Atmega8 chip. To burn the bootloader onto the Atmega8 chip, you'll have to either use an AVR/ICSP programmer or use another Arduino board as the ISP.
- And when you are uploading sketches, be sure to select the correct board (again, the one named "Arduino NG or older w/ ATmega8") from the menu in the Arduino IDE.