Skip to content

PWM_limit State Machine

ThePWM_limit State Machine controls PWM outputs as a function of pre-armed and armed inputs. Provides a delay between assertion of "armed" and a ramp-up of throttle on assertion of the armed signal.

Quick Summary


  • armed: asserted to enable dangerous behaviors such as spinning propellers
  • pre-armed: asserted to enable benign behaviors such as moving control surfaces
  • this input overrides the current state
  • assertion of pre-armed immediately forces behavior of state ON, regardless of current state
  • deassertion of pre-armed reverts behavior to current state


  • INIT and OFF
    • pwm outputs set to disarmed values.
  • RAMP
    • pwm outputs ramp from disarmed values to min values.
  • ON
    • pwm outputs set according to control values.

State Transition Diagram

PWM Limit state machine diagram