#include <BLEDevice.h>

#define SERVICE_UUID "4fafc201-1fb5-459e-8fcc-c5c9c331914b"
#define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361b26a8"

void setup() {
  BLEDevice::init("ESP32-BLE");
  BLEServer *pServer = BLEDevice::createServer();
  BLEService *pService = pServer->createService(SERVICE_UUID); 
  BLECharacteristic *pCharacteristic = pService->createCharacteristic(
                                                  CHARACTERISTIC_UUID, 
                                                  BLECharacteristic::PROPERTY_READ | // 启用读取
                                                  BLECharacteristic::PROPERTY_WRITE  // 启用写入
                                                  );
  pCharacteristic->setValue("Hello World"); // 设置该Characteristic的Value值
                                            // 如果客户端连上设备后没有任何写入的情况下第一次读取到的数据应该是这里设置的值
  pService->start(); 

  BLEDevice::startAdvertising();
}

void loop() {}