I think a block diagram would be helpful. Perhaps I might start one at some point. It'd show:
- main controller ("NAZA" module): main flight controller, contains gyro/accel/barometer, controls motors
- ESCs: turn digital motor control signals into power control for brushless motors; also do same for LEDs
- GPS module: provides GPS data over CAN bus to main controller
- compass module: provides magnetic compass data over CAN bus to main controller
- receiver: receives 5.8Ghz signal from remote, passes DBus signal to main controller
- wifi module: receives video signals from gimbal camera; compresses/encodes it and sends out as 2.4Ghz wifi data; also can receive pitch/camera control, send back to gimbal camera (perhaps via aux CPU)
- main board with aux control CPU: distributes raw battery power to motors, regulates power for electronics, has aux CPU to control gimbal activity, LEDs
- gimbal main board: converts telemetry data from aux CPU to video signal?, decodes gimbal control signals into motor control signals, controls camera recording
- gimbal motor boards: servo control of motor signals; seem to get motor control signals on a common bus
- gimbal camera: provides video feed to gimbal main board
- gimbal power filter board: smooths out power sent to gimbal?
- battery control board: keeps track of battery condition, regulates battery balance charging, controls on/off & battery LEDs