int PinDir=8,PinStep=9;
int KeyIn=0,Direction=0,Speed= 0;
int dataIn;

void setup() {
  Serial.begin(9600);
  pinMode(PinDir,OUTPUT);
pinMode(PinStep,OUTPUT);
Serial.println(" ");
}

void loop() {
  if(Serial.available()>0)KeyIn=Serial.read();
  if(KeyIn=='0')Direction=0;
  if(KeyIn=='+')Direction=1;
  if(KeyIn=='-')Direction=2;
if((KeyIn=='+')||(KeyIn=='-')){
    dataIn = Serial.parseInt();
}

  if(dataIn>0){
    Speed=100-constrain(dataIn,0,100);
    Serial.println(Speed) ;
    dataIn = 0;
  }

if(Direction==1)digitalWrite(PinDir,HIGH);
else digitalWrite(PinDir,LOW);

if (Direction>0){
digitalWrite(PinStep,HIGH);
delay(10+Speed);
digitalWrite(PinStep,LOW);
delay(10+Speed);

}
}