I do not know much electronics.
I have Nano v3 as I2C master, it reads 5-byte packets (of delimtted data) from PC's USB port, processes it and forwards it.
I now need to implement a way to signal PC if something went wrong down the line. I don't want to clutter I2C channel and its just a flag so I think interrupt is best for my purpose.
While writing the ISR function I am not sure if its advisable to write data using Serial, because loop might have read 2-3 bytes of the 5-byte message packet. And I don't know if it will overwrite data coming from PC or what...
What will happen if I Serial.write(0x1) (suddenly, in an ISR function) while loop() was reading data from same Serial?
I don't know how to test this myself.