char receivedChar;
boolean newData = false;

void setup()
{
  Serial.begin(115200);
}

void loop()
{
  recvOneChar();
  showNewData();
}

void recvOneChar()
{
  if (Serial.available() > 0)
  {
    receivedChar = Serial.read();
    newData = true;
  }
}

void showNewData()
{
  if (newData == true)
  {
    for (int i=2; i<10; i++)
    {
      digitalWrite(i,HIGH);
      delay(50);
    }
    for (int i=9; i>1; i--)
    {
      digitalWrite(i,LOW);
      delay(50);
    }
    newData = false;
  }
}