Pure novice, the first time contact code,
Android IDE version 1.8.13, GRBL version is mega25601.1 f version, compile-time error, information is as follows:
Arduino: 1.8.13 (Windows), development board: "Arduino Mega or Mega 2560, ATmega2560 Mega (2560)"
In the file included the from C: \ Users \ longhuwy \ Documents \ Arduino/libraries/GRBL/config. H: 30:0,
The from C: \ Users \ longhuwy \ Documents \ Arduino \ sketch_nov10a \ sketch_nov10a ino: 1:
C: \ Users \ longhuwy \ Documents \ Arduino/libraries/GRBL/GRBL. H: 69:4: error: # error "Required HOMING_CYCLE_0 not defined."
# error "Required HOMING_CYCLE_0 not defined."
^ ~ ~ ~ ~
The exit status 1
Development board for the Arduino Mega or Mega compile-time error 2560,
In the file - & gt; Open
preferences"Compilation process according to detailed output" option
The report contains more information,

Feel it is probably said: undefined required origin, cycle 0
Look is GRBL. H there is something wrong with the line 69, 68-70 lines of code is as follows:
# # ifndef HOMING_CYCLE_0
# error "Required HOMING_CYCLE_0 not defined."
# endif

Can you tell me what's the problem here? Where is defined?