The PWM_limit State Machine controls PWM outputs as a function of pre-armed and armed inputs. It provides a safety ramp-up delay between the assertion of "armed" and full throttle authority.
PWM Limit States
Disarming from any state → OFF. Pre-armed assertion → immediate ON (overrides current state).
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State machine inputs and outputs
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Input Effect
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armed Enables dangerous behaviors (spinning props)
pre-armed Enables benign behaviors (moving surfaces)
Overrides: forces ON state immediately
Deassert: reverts to current armed state
State PWM behavior
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INIT Disarmed values
OFF Disarmed values
RAMP Ramp from disarmed → minimum
ON Full control (follows mixer output)Safety purpose
The RAMP state prevents sudden full-throttle when arming. This gives the pilot time to react if something is wrong. The pre-armed override allows control surfaces to move for pre-flight checks without spinning motors.