APM flight mode switching -- source code explanation

APM There are many ways to change the flight mode in flight control . The most common methods are remote control switching and ground station switching .

Take the remote control switching as an example to explain the flight mode switching logic .

 

APM The source code for the remote control to switch the flight mode is in RC_Channel.cpp In the document RC_Channel_Copter::do_aux_function_change_mode() Function .

const bool success = copter.set_mode() call Copter::set_mode() function , stay set_mode() Call in function mode_from_mode_num() Function to pre switch .new_flightmode Will not immediately switch to the new mode , Instead, it will judge whether to switch to the past according to the equipment status required by the new mode .

If the above items pass the inspection , Then exit the old mode . Set new mode , The switch is successful .

  take flightmode The parent class pointer points to the new child class , stay Copter::fast_loop() Function with 400Hz Frequency call of flightmode->run().

therefore , The operating frequency of each flight mode is 400Hz.