Its my first effort to setup CNC for now I'm using two axis X and Y to build a pen plotter or may be getting them move is enough.

I'm setting up Arduino CNC Shield with DRV8825 drivers on it, stepper motors are RB 17HD0004-7 they are 12V 0.28A I set the DRV8825 accordingly, connections are as below

Motor DRV8825
1. Black....... A1
2. N/A
3. GREEN....B1
4. BLUE.......A2
5. N/A
6. RED.........B3

After that i wrote an Arduino based simple program to move motors X and Y and I was able to move both motors in both directions by just sending pulse.

Now it was the time to download GRBL, after upload GRBL to Arduino and connect through Universal GCode Sender
On setup wizard I setup limit switch as i have installed two for homing the machine, on wizard window i was able to see switches are working and they are normally open. (by pressing switch it shows RED and normally it shows GREEN)

From UGS Jog I can move motors to X and Y directions (both plus and minus directions) If i send command G28 X5 axis moves as expected.

When i press Home button on the UGS motors make a squeaky sound and do not move at all, if I try to move axis by hand they are badly stuck, if i turn of the power again I can move both axis smoothly by hand. I have been spent more than 3 days to solve this issue but no luck.

Here are the current GRBL settings.

$0=10 (step pulse, usec)
$1=25 (step idle delay, msec)
$2=0 (step port invert mask:00000000)
$3=0 (dir port invert mask:00000000)
$4=0 (step enable invert, bool)
$5=0 (limit pins invert, bool)
$6=0 (probe pin invert, bool)
$10=3 (status report mask:00000011)
$11=0.010 (junction deviation, mm)
$12=0.002 (arc tolerance, mm)
$13=0 (report inches, bool)
$20=0 (soft limits, bool)
$21=1 (hard limits, bool)
$22=1 (homing cycle, bool)
$23=3 (homing dir invert mask:00000011)
$24=25.000 (homing feed, mm/min)
$25=500.000 (homing seek, mm/min)
$26=250 (homing debounce, msec)
$27=5.000 (homing pull-off, mm)
$100=1000.000 (x, step/mm)
$101=100.000 (y, step/mm)
$102=250.000 (z, step/mm)
$110=500.000 (x max rate, mm/min)
$111=500.000 (y max rate, mm/min)
$112=500.000 (z max rate, mm/min)
$120=10.000 (x accel, mm/sec^2)
$121=10.000 (y accel, mm/sec^2)
$122=10.000 (z accel, mm/sec^2)
$130=200.000 (x max travel, mm)
$131=200.000 (y max travel, mm)
$132=200.000 (z max travel, mm)