I know this is an old post, but I came here looking for an answer and left without one.
So I decided to come back and post.
//simple A4988 connection
//jumper reset and sleep together
//connect VDD to Arduino 3.3v or 5v
//connect GND to Arduino GND (GND near VDD)
//connect 1A and 1B to stepper coil 1
//connect 2A and 2B to stepper coil 2
//connect VMOT to power source (9v battery + term)
//connect GRD to power source (9v battery - term)
int stp = 13; //connect pin 13 to step
int dir = 12; // connect pin 12 to dir
int a = 0; // gen counter
void setup()
{
pinMode(stp, OUTPUT);
pinMode(dir, OUTPUT);
}
void loop()
{
if (a < 200) //sweep 200 step in dir 1
{
a++;
digitalWrite(stp, HIGH);
delay(10);
digitalWrite(stp, LOW);
delay(10);
}
else
{
digitalWrite(dir, HIGH);
a++;
digitalWrite(stp, HIGH);
delay(10);
digitalWrite(stp, LOW);
delay(10);
if (a>400) //sweep 200 in dir 2
{
a = 0;
digitalWrite(dir, LOW);
}
}
}