A safety switch can be used to enable/disable the outputs to motors and servos.
Constant blinking - system is initialising
Intermittent blinking - system is ready. press the safety switch to enable output to the motors.
Solid - safety switch has been pressed, motors and servos are able to move once the vehicle is armed.
Configuring the Safety Switch¶
BRD_SAFETY_DEFLT = 0 to disable the switch.(
BRD_SAFETYENABLEin older firmware versions)
BRD_SAFETY_MASK can be used to set which individual channels are enabled/disabled with the safety switch
BRD_SAFETYOPTION This bitmask controls the operational limits of the safety button. It allows you to control if the safety button can be used for safety enable and/or disable, and whether the button is active if armed. Also, if the safety state is forced on upon disarming.
Using the Safety Switch to force I/O board firmware update¶
If the safety switch is held down for the first few seconds after a Pixhawk is powered up, the I/O firmware is reloaded.
This is normally not required but in some rare cases is required after a firmware upload if you hear the “Start up Failed” sound after startup (see Sounds wiki page).
A Pixhawk has two CPUs, the main CPU (aka FMU) is where ArduPilot runs. There is a separate I/O CPU which is responsible for some I/O including PWM outputs to the MAIN OUT channels. Pixracers only have the main CPU.