Bring GcodeCNCDemo2Axis.ino to work and scaling

Hello, I am trying to use your program GcodeCNCDemo2Axis.ino for a stepper motor drive of a DVD sled. Thank you very much for the informative web page and the programs.

In order to make the program work I needed to make a modification: line 185 must read: ptr=strchr(ptr,' ')+1; A compiler warning can be avoided, when you write in line 181 while((int)ptr>1 && *ptr && ptr<buffer+sofar) { // cast to int

One question about scaling. The stepper motor in use needs 20 steps for one turn, and moves the head on the spindel 3 mm (from datasheet). When in config.h I adopt: #define STEPS_PER_TURN (20) I get with the command: G01 F10 X30; (30 mm?) a movement of about 5 mm. When I try to scale with the parameter STEPS_PER_TURN (xx) it behaves strange. How can I scale Xmm to the actual movement?

Another question is MICROSTEP. The actual movement with module AMS1 (adafruit motor control V1 with 74HCT595) sounds like SINGLE stepping. I have used from adafruit the program "steppertest.pde" which goes endless forth and back 100 steps in different step modes.

Regards, Rudolf

p.s. I wrote an issue, because the "Reply" function on the web page https://www.marginallyclever.com/2013/08/how-to-build-an-2-axis-arduino-cnc-gcode-interpreter/ does not work. The "Post Comment" button overlaps the captcha field.