In order to build a sampler, I use a stepper motor to move a tray along a 
linear rail. I'm using a NEMA 17 size motor with a step angle of 1.8° and a 
peak current of 1.68A/phase.
The stepper motor and the driver are mounted as follows: 

<https://wiki.mchobby.be/images/c/cf/STEPSTK-DRV8825-WIRE_01.png>

I also set the current limit to 1.0 using the formula: Current Limit = VREF 
x 2 x 70% (for full step mode)

Finally, my motor connection is as follows: (after checking the pairs with 
a multimeter)
B2 : blue ; B1: red ; A1: green ; A2: black.

My problem :
-> all the connections seem ok but my stepper motor makes an abnormal 
strident noise as soon as I feed it...
-> when the power is on, its impossible to turn the motor by hand
-> during my first tests with the stepper motor( 1 week ago), he responded 
well to the code (despite the shrill noise). But today he doesnt answer at 
all. I think the condition of the motor is getting worse as I test it.

#import Arduino library
from bbio import *

#Define pins
stepPin = GPIO2_3
dirPin = GPIO2_4

#Set the pins as output
def setup():
             pinMode(stepPin, OUTPUT)
             pinMode(dirPin, OUTPUT)

def loop():
             digitalWrite(dirPin, HIGH)
             for i in xrange(0,200,2):
                         digitalWrite(stepPin, HIGH)
                         delayMicroseconds(500)
                         digitalWrite(stepPin, LOW)
                         delayMicroseconds(500)

              delay(1000)

run(setup, loop)

Has anyone ever used this driver to control the stepper motor? I said that 
I already tried to control it with an EasyDriver but my stepper motor needs a 
minimum current of 1 to 1.2A to activate the coils (easydriver: max 0.75A 
continuously or otherwise 0.85A).

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