L298 Dual Full Bridge L298N Stepper/DC Motor Driver Shield 46V/2A for Arduino

Schematic

Click on image to zoom.

Terminal Block Pinout

Sample Sketch

/*
 * The circuit:
 * L298N INPUT1 to digital pin 13
 * L298N INPUT2 to digital pin 12
 * L298N INPUT3 to digital pin 11
 * L298N INPUT4 to digital pin 8
 * L298N ENABLE_A to digital pin 10 (PWM)
 * L298N ENABLE_B to digital pin 9 (PWM)
 */

// motor A
int dir1PinA = 13;
int dir2PinA = 12;
int speedPinA = 10;

// motor B
int dir1PinB = 11;
int dir2PinB = 8;
int speedPinB = 9;

unsigned long time;
int speed;
int dir;

void setup() 
{
	pinMode(dir1PinA, OUTPUT);
	pinMode(dir2PinA, OUTPUT);
	pinMode(speedPinA, OUTPUT);
	pinMode(dir1PinB, OUTPUT);
	pinMode(dir2PinB, OUTPUT);
	pinMode(speedPinB, OUTPUT);
	time = millis();
	speed = 0;
	dir = 1;
}

void loop() 
{
	analogWrite(speedPinA, speed);
	analogWrite(speedPinB, 255 - speed);

	// set direction
	if (1 == dir) 
	{
		digitalWrite(dir1PinA, LOW);
		digitalWrite(dir2PinA, HIGH);
		digitalWrite(dir1PinB, HIGH);
		digitalWrite(dir2PinB, LOW);
	}
	else 
	{
		digitalWrite(dir1PinA, HIGH);
		digitalWrite(dir2PinA, LOW);
		digitalWrite(dir1PinB, LOW);
		digitalWrite(dir2PinB, HIGH);
	}

	if (millis() - time > 5000) 
	{
		time = millis();
		speed += 20;
		if (speed > 255)
			speed = 0;
		if (1 == dir)
			dir = 0;
		else
			dir =1;
	}
}