Hi, I'm drawing Arduino Mega schematic for my project and I have some question that I appreciate your help by answering them.
1- In the attached pic. the parts in the blue circle, (L1, F1, Z1, Z2) can I ignore them in my circuit? If not, can I replace them with other values (please mention the possible value), because these parts are not available in the SMT service of my supplier.
2- In the yellow circle. When do I have to connect both grounds and when I should not?
3- Why I have two ICSP in Arduino Mega (one for ATMega2560 chip and one for ATMEGA16U2-MU)? and to which one I have to use to burn the bootloader?