void CarDataInput(byte btMsgsIndx, byte *btDataBuffer, byte *someTimes = nullptr){
  *btDataBuffer = 10;
  if (someTimes != nullptr){
    *someTimes=100;
    *btDataBuffer = 20;
  }

}

byte indx,buff;


void setup() {
  // put your setup code here, to run once:

Serial.begin(115200);
byte st=0;
CarDataInput(indx,&buff);
Serial.print("2 Params ");
Serial.println(st);
CarDataInput(indx,&buff,&st);
Serial.print("3 Params ");
Serial.println(st);



}

void loop() {
  // put your main code here, to run repeatedly:

}