swift - corebluetooth写入2字节

let centralManager = CBCentralManager(delegate: self, queue: nil)

extension ViewController: CBCentralManagerDelegate {
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        if central.state == .poweredOn {
            // 蓝牙已打开，可以开始扫描外围设备
            central.scanForPeripherals(withServices: nil, options: nil)
        } else {
            // 蓝牙未打开或不可用
        }
    }
    
    func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
        // 扫描到外围设备后的处理逻辑
    }
}

func centralManager(_ central: CBCentralManager, didDiscover peripheral: CBPeripheral, advertisementData: [String : Any], rssi RSSI: NSNumber) {
    if peripheral.name == "设备名称" {
        central.stopScan() // 停止扫描
        central.connect(peripheral, options: nil) // 连接设备
    }
}

func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
    let data = Data(bytes: [0x01, 0x02]) // 要写入的2字节数据
    let characteristicUUID = CBUUID(string: "特征UUID") // 外围设备的特征UUID
    let serviceUUID = CBUUID(string: "服务UUID") // 外围设备的服务UUID
    
    peripheral.discoverServices([serviceUUID]) // 发现服务
    
    peripheral.delegate = self
}

func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
    if let service = peripheral.services?.first {
        let characteristicUUID = CBUUID(string: "特征UUID") // 外围设备的特征UUID
        
        peripheral.discoverCharacteristics([characteristicUUID], for: service) // 发现特征
    }
}

func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
    if let characteristic = service.characteristics?.first {
        peripheral.writeValue(data, for: characteristic, type: .withResponse) // 写入数据
    }
}