not working with mega2560 + cnc shield v3

[darkworks]

i have connected mega 2560 + cnc shield + 3 stepper motors nema 17 and uploaded this grbl mega but its not moving the motors when i send gcode ,
can u tell me where is the configuration file of this grbl i mean there should be some sort of config file where u mention step , dir and enable pins of your board into it so that it work ,

thanks

[chamnit]

Grbl on Mega has a different pin configuration that isn’t compatible with Arduino Uno shields. See the wiki for the pin outs and you’ll have to find a way to connect them correctly.

[drf5n]

Oh my-- it is very different. The CNC Shield V3 schematic from https://blog.protoneer.co.nz/arduino-cnc-shield/ has the step pins to the Mega's 2,3,4, which are PE4,PE5,PG5, which aren't on the same port, etc... The definitions in

grbl-Mega/grbl/cpu_map.h

Line 29 in df87b36

#ifdef CPU_MAP_2560_INITIAL // (Arduino Mega 2560) Working @EliteEng

map those pins to Port A, PA2,PA3, PA4 on the Arduino Mega's pins 24,25,26, etc ...

It looks like one could use the V3 shield's double-row of connectors for XSTEP/DIR...ASTEP/DIR with jumpers to the MEGA's extended pins. grbl doesn't do 4 axes of steppers, so it's these 9 wires up to the CNC Shield V3 for control:

Mega 13 >>  EN   |  GND
Mega 24 >> XSTEP | XDIR << Mega 30
Mega 25 >> YSTEP | YDIR << Mega 31
Mega 26 >> ZSTEP | ZDIR << Mega 32
           ASTEP | ADIR 
Mega 5V >>    5V | GND  << Mega GND

Then bypass the board and hook your X,Y,Z stops up as 10,11,12; and RESET, HOLD, RESUME, DOOR as A8,A9, A10,A11, and the spindle EN,DIR as 6,7, and the coolant Flood/Mist as 8,9.

The CNC Shield V3 won't work neatly attached to the Arduino Mega as it does to the Uno https://github.com/gnea/grbl/wiki/Connecting-Grbl

It might be nice do do an image like https://github.com/gnea/gnea-Media/raw/master/Grbl%20Help/Grbl_Pin_Diagram_v0.9+.png?raw=true for the Mega2560.