Receiving and store two bytes serial (RC Car Xbee)

Hello Together

I'm working on a PS3 controlled RC Car. I am communicating over two arduino uno and two xbee S2 modules.

Now to my problem:

How can i get two bytes from the serial line and match them to the right servo. The first byte(value0-180) is for the steering. The second is for Speedcontrol ESC.

I wrote a code for only one byte and that works quite well.

Greatings
Fabrice

#include <Servo.h> 
Servo myservo;
byte incomingByte = 90;

void setup() {
   myservo.attach(7);
  // initialize serial communication:
  Serial.begin(9600);
}

void loop() {
  // see if there's incoming serial data:
  if (Serial.available()>0) 
  {
    // read the oldest byte in the serial buffer:
    incomingByte = Serial.read();
    myservo.write(incomingByte);
    }
}

sender:

#include <PS3USB.h>


USB Usb;

PS3USB PS3(&Usb); // This will just create the instance

byte potvallenkung = 90;
int potvalspeed = 90;
int potvalbreak = 90;
byte speedval = 90;
String datapacket;
uint8_t state = 0;

void setup() {
  Serial.begin(9600);
  while (!Serial); // Wait for serial port to connect 
  if (Usb.Init() == -1) 
  {
    Serial.print(F("\r\nOSC did not start"));
    while (1); //halt
  }
  Serial.print(F("\r\nPS3 USB Library Started"));
}
void loop() 
  {
    Usb.Task();
    //Auswertung Daten Lenkung
    potvallenkung = PS3.getAnalogHat(LeftHatX);  // Linker Stick X-Achse auslesen
    potvallenkung = map(potvallenkung, 0, 255, 0, 180); // Analoger wert umrechnen für Servolibrary
    potvallenkung = constrain(potvallenkung, 5, 175);  // Sicherheitsbereich für servo definieren min 5° max 175° variable als byte

    //Auswertung Daten Speedcontrol
    potvalspeed = PS3.getAnalogButton(R2);
    potvalspeed = map(potvalspeed, 0, 255, 90, 180);
    potvalspeed = constrain(potvalspeed, 90, 180);
    
    potvalbreak = PS3.getAnalogButton(L2);
    potvalbreak = map(potvalbreak, 0, 255, 90, 0);
    potvalbreak = constrain(potvalbreak, 0, 90);

    speedval = ((potvalspeed + potvalbreak)-90);
    Serial.write(potvalspeed);
    Serial.write(speedval);

    /*datapacket = (String((potvallenkung+100))+String((speedval+100)));
    int dataint = datapacket.toInt();
    Serial.println(dataint);
    delay(20);*/

  }

Have a look at the examples in Serial Input Basics. The system in the 3rd example will be most reliable. There is also a parse example.

...R