Ahh sorry I didnt understand what you meant by it.
Beside from the amperage, do you think there would be any problem with the circuit?
Especially the ground line to XMOS from Motor Driver. Since the motor controller itself is already powered with battery, Vcc is not required but a Ground connection is required.
I think you should just power servo from motor controller(typical) and use a seperate supply for xmos while using level shifters for signal wires and bluetooth lines if needed. Otherwise you need a 2a supply for servo and another supply for xmos since a 7.2v nom battery will be closer to 8v fully charged. and still require level shifters for safety of signal lines. Some servos do not work well with a 3v3 signal either, but thats easy to test.
The red and black from motor controllee are typically just the power lines for servo and a receiver so they're actually a great way to power servo. I just dont think it's a good place to get power for xmos since it seems to limit current to 1.5a, which means it is only enough for servo alone in your set up. If you wait about 10 hours. I'll have time to do a schematic to better explain. For the most part what you have there should work, I just think you should take advantage of the fact the motor controller already has a small builtin power supply.
Hmm I hear what you say but unfortunately, the not connected pin from motor controller does not have any voltage. Thats why I thought I need to power servo alone from another supply or via an isolator.
So yea, something between 1-2a is what you want for the servo. But using the motor ground then may not be feasible if the motor controllers internal bec is no longer functioning or damaged and shorting. Verify with everything plugged in to battery that the black wire from motor controller is a good ground. If it is it You're right in connecting that to the xmos board and then just use 3.3v to send signal to it, no level shifters needed unless it doesn't respond to 3.3v signal. The servo should still have level shifters though. Those servos typically work best with a 6v supply, but 5v is ok too so that's essentially what you're looking for.
If you have space for two power supplies I'd recommend one for xmos/other electrics and one for servo, both run directly from battery for source. Doing that you know your ground level is steady throughout and it will simplify things by removing level shifter for servo/motor controller. Then you just need level shifters for your sonar sensors. You should do this method if the motor controllers internal bec ground wire is damaged, shorting, or open.
