//https://forum.arduino.cc/t/l298n-motor-shield/52627/3

//L298N Motor Shield V3 flamingoeda

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