I have a latching "emergency stop"-type NC button mounted on my machine using this config:
# Kill button (used to be called pause) maybe assigned to a different pin, set to the onboard pin by default
kill_button_enable true # set to true to enable a kill button
kill_button_pin 2.12!^ # kill button pin. default is same as pause button 2.12 (2.11 is anot
kill_button_toggle_enable true # allows for latching estop button
unkill_enable false
If I don't press it before turning on the power (the contact is closed), the board will not boot, the leds just light up and stay lit, nothing will help but resetting it. If I press the button before turning on the power (the contact is open), it boots normally. I can then exit the alarm state using M999 and continue using the board normally. If I press the button during movement, it works as expected.