For GRBL1.1

The control card has the following connection options:

• Connection possibility for drivers or motors for 3 axes, also several motors/drivers per axis.
• Then of course limit switches for all 3 axes, also 2 limit switches per axis.
• Relay output to switch cooling water.
• Probe; length sensor, touch plate, stylus etc. can be connected in parallel.
• Connection for buttons; program start, program pause, program continue, abort and hardware reset.
• Connection for frequency converter/HF spindle, 0-10V, or 0-5V output, adjustable.
• Switching of DCM/FOR, for the frequency inverter.
• Extra relay output for switching milling machines without frequency converter e.g. AMB (Kress) also AMB machines with 0-10V input.
• Possibility to display the switching status of the limit switches.
• Connection for push button - Hardware reset

No special Nano necessary, works with the standard Nano V3 5V and bootloader.

Further information can be found at : ArduinoClub - GRBL1.1

Take a look at the connection diagram : Diagram