                         Serial.write("err unknown config\n");
                 }
                 break;
-            case 's': // status
+            case '?': // get config/status
                 while (!Serial.available());
                 switch (arg = Serial.read()) {
                     case '0': // check if reference point exists

                        writePos(arg, posZ);
                        break;
                    default:
                        Serial.write("err unknown status\n");
                        Serial.write(arg);
                }
                break;
            case 'p': // ping

    int steps = Serial.parseInt();
    pos += steps;
    motor.rotateSteps(steps);
    succes();
}

void writePos(char name, int var) {
    if (configured) {
        Serial.write("set pos.");
        Serial.write(name);
        Serial.write(' ');
        Serial.print(var);
        Serial.write('\n');
    } else {
        Serial.write("err not configured\n");
    }
}

void succes() {
    Serial.write("ok.\n");
}

void loop() {
