#include <AccelStepper.h> // https://github.com/adafruit/AccelStepper/blob/master/AccelStepper.h

#define dirPin 2
#define stepPin 3
#define motorInterfaceType 1 // set to 1 when using a driver board

AccelStepper stepper = AccelStepper(motorInterfaceType, stepPin, dirPin); // Create instance of AccelStepper class:

int maxSpeed = 800; // maximum steps per second
int accelRate = 100; // rate of acceleration

void setup() {
  stepper.setMaxSpeed(maxSpeed);
  stepper.setAcceleration(accelRate);
}

void loop() {
  stepper.moveTo(1600);    // Set the target position: (blocking)
  stepper.runToPosition(); // Run to target position with set speed and accel/decel
  delay(1000);

  stepper.moveTo(0);       // Move back to zero (blocking)
  stepper.runToPosition(); // run to target position with set speed and accel/decel
  delay(1000);
}

/*
           +-------------------------+
  LOW=ENBL | ENABLE    A4988    VMOT | 8-35vdc ---+ 100uf electro cap
           | MS1                 GND | gnd -------+ pwr spike protect
           | MS2                  2B | stepper 2B
           | MS3                  2A | stepper 2A
       SLP | RESET                1A | stepper 1A
       RST | SLEEP                1B | stepper 1B
     Pin 3 | STEP                VDD | 5vdc
     Pin 2 | DIR                 GND | gnd
           +-------------------------+

           MS1	MS2	 MS3   Step resolution
           Low  Low	 Low   Full step
           High Low	 Low   1/2 step
           Low  High Low   1/4 step
           High High Low   1/8 step
           High High High  1/16 step

           SET DRIVER CURRENT LIMIT
           1. Power A4988 driver (Vdd, GND)
           2. Connect RST to SLP
           3. Disconnect motor
           4. Apply USB power
           5. Calculate current limit: Current Limit = Vref ÷ (8 × Rcs)
           6. A current limit of 1A (standard) needs Vref of 540mV
           7. Adjust POT while measuring Vref at GND to POT (metal screw)
           8. If the motor is making a lot of noise,  lower the current limit
*/