#include <SoftwareSerial.h>

#define dirA 7
#define dirB 8

SoftwareSerial mySerial(0, 1); // RX, TX
String line;
  int dato;

void setup() {
   // set the data rate for the SoftwareSerial port
  mySerial.begin(9600);
  pinMode(dirA,OUTPUT);
  pinMode(dirB,OUTPUT);
  digitalWrite(dirB,LOW);

}

void loop() { // run over and over
  if (mySerial.available()) {
    line=mySerial.readString();
    dato=(line.charAt(0)-48)*100+(line.charAt(1)-48)*10+(line.charAt(2)-48);
    //mySerial.println(dato);
    analogWrite(dirA,dato);
  }
 
}