I have just learned a bit on the ISP way of programming an ATMega328P with the Arduino ISP (IDE version 1.8.5), and managed to burn a bootloader to it and also upload a sketch this way. However, there are two things that I cannot find any answers for.
- A factory fresh empty chip needs to have the fuses set, which happens when I burn the bootloader. Then when I upload a sketch (via ISP), the bootloader is gone - but will the fuses stay ?
- Suppose I have a 328P with a pre-loaded sketch that use pins 11 (MOSI) & 13 (SCK) as high outputs, is there a safe way to connect it to a master "arduino as isp" (in order to re-program it) ? Or would I have to change the sketch output pins first via ftdi/ch340 ?
Any advice appreciated.