HI,
I would like to wire the 3 servos of the Romi Arm on the Romi 32U4 and have difficulties to find the pins to use on the 32U4 board.
Except the 32U4 user guide inform about the usage of Timer 3 for servo… but no more information about wiring.
The most convenient pins to choose are the ones where the expansion headers allow you to get GND, power, and an I/O pin in a row. The servo library, whether original or modified to use timer 3, can control servos on any pin. 5V would be the most appropriate power source for the servos and some of the power rails towards the front of the board can optionally be connected to an adjacent 5V pin, which would make them good places to connect servos.
I have replied to your separate thread here, which I think answers most of your questions. However, to clarify about the servo wires, the green wire is optional and gives access directly to the servos position feedback potentiometer. If you want to use the feedback, you would need to connect it to a pin on the Romi 32U4 Control Board that is capable of reading analog signals, but it is not needed to use the servo normally.