G Codes in Marlin
See list at the Marlin site - http://marlinfw.org/meta/gcode/
IO Pin Activation
- M42 -  - Ex: M42 P5 S255 (set digital pin 5 to on). Internet sez: For a non-PWM digital pin you need to put S0 (or any value <128) to turn off and S255 (or any value >=128) to turn on.
- Which pins are available?
- D0 is the first most convenient at AUX ports - see Mega pins - 
- For 2 adjacent pins with ground - use GND - D63.
- Thus - to turn on a gas solenoid for the CNC Torch Table v19.10, use M42 P63 S255. To turn it off, set state to 0.
- D1 if use 5v gnd D1 as an adjacent triplet. This would be M42 P1 S255
- M42 P57 S0