[Mendy]

I’m interested in writing my own custom firmware for the Arduino, is there any documentation on what each of the pcb pins is doing?

[Angel LM]

Hi Mendy!

You can see the configuration files of GRBL I modified in order to make it work for Thor: https://github.com/angellm/grbl

However, these are the most relevant ones:

Steppers ENABLE/DISABLE signal

#define STEPPERS_DISABLE_BIT 1 // MEGA2560 Digital Pin 40

Steppers STEP signals

#define A_STEP_BIT    6 // MEGA2560 Digital Pin 28
#define B_STEP_BIT    4 // MEGA2560 Digital Pin 26
#define C_STEP_BIT    2 // MEGA2560 Digital Pin 24
#define D_STEP_BIT    0 // MEGA2560 Digital Pin 22
#define E_STEP_BIT    1 // MEGA2560 Digital Pin 23
#define F_STEP_BIT    3 // MEGA2560 Digital Pin 25
#define G_STEP_BIT    5 // MEGA2560 Digital Pin 27

Steppers DIR signals

#define A_DIRECTION_BIT   1 // MEGA2560 Digital Pin 36
#define B_DIRECTION_BIT   3 // MEGA2560 Digital Pin 34
#define C_DIRECTION_BIT   5 // MEGA2560 Digital Pin 32
#define D_DIRECTION_BIT   7 // MEGA2560 Digital Pin 30
#define E_DIRECTION_BIT   6 // MEGA2560 Digital Pin 31
#define F_DIRECTION_BIT   4 // MEGA2560 Digital Pin 33
#define G_DIRECTION_BIT   2 // MEGA2560 Digital Pin 35

Endstop signals

#define A_LIMIT_BIT     7 // MEGA2560 Digital Pin 42
#define B_LIMIT_BIT     5 // MEGA2560 Digital Pin 44
#define C_LIMIT_BIT     5 // MEGA2560 Digital Pin 44 //3 // MEGA2560 Digital Pin 46
#define D_LIMIT_BIT     1 // MEGA2560 Digital Pin 48
#define E_LIMIT_BIT     0 // MEGA2560 Digital Pin 49
#define F_LIMIT_BIT     2 // MEGA2560 Digital Pin 47
#define G_LIMIT_BIT     2 // MEGA2560 Digital Pin 47//4 // MEGA2560 Digital Pin 45

Tool signal:

#define SPINDLE_ENABLE_BIT 4 // MEGA2560 Digital Pin 7

[Angel LM]

Some time ago I also thought about developing my own firmware. Actually, with GRBL, Thor’s movements are not like those of a normal robot, since the movement of all motors starts and ends at the same time, making linear movements not possible. Or at least I think so.
If you decide to design your own firmware, please keep me updated!

[Mendy]

Thanks for the information! I’m currently looking into the feasibility of doing custom firmware.

If I end up doing it it’ll most probably be just the controller software without a GUI.

[Author]

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