#define pinSH_CP  4   //Pino Clock  DIR_CLK
#define pinST_CP  12  //Pino Latch  DIR_LATCH
#define pinDS     8   //Pino Data   DIR_SER
#define pinEnable 7   //Pino Enable DIR_EN

#define pinMotor1PWM 11
#define pinMotor2PWM 3
#define pinMotor3PWM 5
#define pinMotor4PWM 6

#define bitMotor1A 2
#define bitMotor1B 3
#define bitMotor2A 1
#define bitMotor2B 4
#define bitMotor3A 5
#define bitMotor3B 7
#define bitMotor4A 0
#define bitMotor4B 6

void ci74HC595Write(byte pino, bool estado);

void setup() {
   pinMode(pinSH_CP, OUTPUT);
   pinMode(pinST_CP, OUTPUT);
   pinMode(pinEnable, OUTPUT);
   pinMode(pinDS, OUTPUT);

   pinMode(pinMotor1PWM, OUTPUT);
   digitalWrite(pinEnable, LOW);

   Serial.begin(9600);
}

void loop() {
  ci74HC595Write(bitMotor1A, HIGH);
  ci74HC595Write(bitMotor1B, LOW);
  analogWrite(pinMotor1PWM, 120);
  delay(1000);

  analogWrite(pinMotor1PWM, 0);
  delay(1000);

  ci74HC595Write(bitMotor1A, LOW);
  ci74HC595Write(bitMotor1B, HIGH);
  analogWrite(pinMotor1PWM, 120);
  delay(1000);

  analogWrite(pinMotor1PWM, 0);
  delay(1000);
}

void ci74HC595Write(byte pino, bool estado) {
  static byte ciBuffer;
  bitWrite(ciBuffer, pino , estado);
  
  digitalWrite(pinST_CP, LOW); //Inicia a Transmissão
  digitalWrite(pinDS, LOW);    //Apaga Tudo para Preparar Transmissão
  digitalWrite(pinSH_CP, LOW);
  for (int nB = 7; nB >= 0; nB--) {
      digitalWrite(pinSH_CP, LOW);  //Baixa o Clock      
      digitalWrite(pinDS,  bitRead(ciBuffer, nB) );     //Escreve o BIT
      digitalWrite(pinSH_CP, HIGH); //Eleva o Clock
      digitalWrite(pinDS, LOW);     //Baixa o Data para Previnir Vazamento      
  }  
  digitalWrite(pinST_CP, HIGH);  //Finaliza a Transmissão
}