XIAO ESP32C3を使ってみる　その５（Bluefluit Connect、iPhoneとBLE通信）

#include <BLEDevice.h>
#include <BLEServer.h>
#include <BLEUtils.h>
#include <BLE2902.h>

BLEServer *pServer = NULL;
BLECharacteristic *pTxCharacteristic;
bool deviceConnected = false;
bool oldDeviceConnected = false;

// See the following for generating UUIDs:
// https://www.uuidgenerator.net/

#define SERVICE_UUID "6E400001-B5A3-F393-E0A9-E50E24DCCA9E"  // UART service UUID
#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"

const int pin = A0;

void setup() {
  Serial.begin(115200);
  BLE_setup("XIAO ESP32C3");  
}

void loop() {
  if (deviceConnected) {
    char str[8];
    int data = analogRead(pin);

    sprintf(str, "%d\n", data);
    Serial.println(str);
    pTxCharacteristic->setValue(str);
    pTxCharacteristic->notify();
    delay(10);  // bluetooth stack will go into congestion, if too many packets are sent
  }

  // disconnecting
  if (!deviceConnected && oldDeviceConnected) {
    delay(500);                   // give the bluetooth stack the chance to get things ready
    pServer->startAdvertising();  // restart advertising
    Serial.println("start advertising");
    oldDeviceConnected = deviceConnected;
  }
  // connecting
  if (deviceConnected && !oldDeviceConnected) {
    // do stuff here on connecting
    oldDeviceConnected = deviceConnected;
  }
}

class MyServerCallbacks : public BLEServerCallbacks {
  void onConnect(BLEServer *pServer) {
    deviceConnected = true;
  };

  void onDisconnect(BLEServer *pServer) {
    deviceConnected = false;
  }
};

class MyCallbacks : public BLECharacteristicCallbacks {
  void onWrite(BLECharacteristic *pCharacteristic) {
    String rxValue = pCharacteristic->getValue();

    if (rxValue.length() > 0) {
      Serial.println("*********");
      Serial.print("Received Value: ");
      for (int i = 0; i < rxValue.length(); i++) {
        Serial.print(rxValue[i]);
      }

      Serial.println();
      Serial.println("*********");
    }
  }
};

void BLE_setup(String name) {
  // Create the BLE Device
  BLEDevice::init(name);

  // Create the BLE Server
  pServer = BLEDevice::createServer();
  pServer->setCallbacks(new MyServerCallbacks());

  // Create the BLE Service
  BLEService *pService = pServer->createService(SERVICE_UUID);

  // Create a BLE Characteristic
  pTxCharacteristic = pService->createCharacteristic(CHARACTERISTIC_UUID_TX, BLECharacteristic::PROPERTY_NOTIFY);
  pTxCharacteristic->addDescriptor(new BLE2902());
  BLECharacteristic *pRxCharacteristic = pService->createCharacteristic(CHARACTERISTIC_UUID_RX, BLECharacteristic::PROPERTY_WRITE);
  pRxCharacteristic->setCallbacks(new MyCallbacks());

  // Start the service
  pService->start();

  // Start advertising
  pServer->getAdvertising()->start();
  Serial.println("Waiting a client connection to notify...");
}