if(SD.exists(jsonFileName)){
    Serial.println("++Config file");
    DynamicJsonDocument jsonData(JSONMAXCAPACITY) ;
    jsonFile = SD.open(jsonFileName,FILE_READ);
    if(!jsonFile)
    {
      Serial.println("Can't read conf file.");
    }
  /*  while (jsonFile.available()) {
      Serial.write(jsonFile.read());
    }*/
    deserializeJson(jsonData, jsonFile);
    auto error = deserializeJson(jsonData, jsonFile);
    if (error) {
      Serial.print(F("deserializeJson() failed with code "));
      Serial.println(error.c_str());
      return;
    }
    const char* value = jsonData["name"];
    Serial.println(value);
    jsonFile.close();