Question

我在Windows 10上使用华硕BT-400。

我已成功连接到设备，读取了所有特征/属性，并写入了特征。但是，我有一个要订阅通知的特征（我已经确认该特征具有notify属性），并且遇到了错误。

当我遵循代码执行时，看起来像在gatt.js中的notify函数中，我正在获取与错误相关的操作码。

Gatt.prototype.notify = function(serviceUuid, characteristicUuid, notify) {
  var characteristic = this._characteristics[serviceUuid][characteristicUuid];

  this._queueCommand(this.readByTypeRequest(characteristic.startHandle, characteristic.endHandle, GATT_CLIENT_CHARAC_CFG_UUID), function(data) {
    var opcode = data[0];

    if (opcode === ATT_OP_READ_BY_TYPE_RESP) {
      var type = data[1];
      var handle = data.readUInt16LE(2);
      var value = data.readUInt16LE(4);

      var useNotify = characteristic.properties & 0x10;
      var useIndicate = characteristic.properties & 0x20;

      if (notify) {
        if (useNotify) {
          value |= 0x0001;
        } else if (useIndicate) {
          value |= 0x0002;
        }
      } else {
        if (useNotify) {
          value &= 0xfffe;
        } else if (useIndicate) {
          value &= 0xfffd;
        }
      }

      var valueBuffer = new Buffer(2);
      valueBuffer.writeUInt16LE(value, 0);

      this._queueCommand(this.writeRequest(handle, valueBuffer, false), function(data) {
        var opcode = data[0];

        if (opcode === ATT_OP_WRITE_RESP) {
          this.emit('notify', this._address, serviceUuid, characteristicUuid, notify);
        }
      }.bind(this));
    }
  }.bind(this));
};

回调中“ data”的值为：{1，8，54，0，10}。

此外，这就是我称之为的特征：

Characteristic
descriptors: null
name: null
properties: (5) ["read", "writeWithoutResponse", "write", "notify", "indicate"]
type: null
uuid: "495353431e4d4bd9ba6123c647249616"
_events: {data: ƒ}
_eventsCount: 1
_noble: Noble {initialized: true, address: "5c:f3:70:94:4b:01", _state: "poweredOn", _bindings: NobleBindings, _peripherals: {…}, …}
_peripheralId: "3481f4141bf0"
_serviceUuid: "49535343fe7d4ae58fa99fafd205e455"
__proto__: EventEmitter

当我在这个特性上调用discoverDescriptors时：

在该特征上调用discoverDescriptors的结果：

Descriptor {
  _noble:
   Noble {
     initialized: true,
     address: '5c:f3:70:94:4b:01',
     _state: 'poweredOn',
     _bindings:
      NobleBindings {
        _state: 'poweredOn',
        _addresses: [Object],
        _addresseTypes: [Object],
        _connectable: [Object],
        _pendingConnectionUuid: null,
        _connectionQueue: [],
        _handles: [Object],
        _gatts: [Object],
        _aclStreams: [Object],
        _signalings: [Object],
        _hci: [Hci],
        _gap: [Gap],
        _events: [Object],
        _eventsCount: 21,
        onSigIntBinded: [Function: bound ],
        _scanServiceUuids: [] },
     _peripherals:
      { '574d3263441d': [Peripheral], '3481f4141bf0': [Peripheral] },
     _services: { '574d3263441d': {}, '3481f4141bf0': [Object] },
     _characteristics: { '574d3263441d': {}, '3481f4141bf0': [Object] },
     _descriptors: { '574d3263441d': {}, '3481f4141bf0': [Object] },
     _discoveredPeripheralUUids: [ '574d3263441d', '3481f4141bf0' ],
     _events:
      [Object: null prototype] {
        warning: [Function: bound ],
        newListener: [Function: bound ],
        stateChange: [Function],
        discover: [Function] },
     _eventsCount: 4,
     _allowDuplicates: undefined },
  _peripheralId: '3481f4141bf0',
  _serviceUuid: '49535343fe7d4ae58fa99fafd205e455',
  _characteristicUuid: '495353431e4d4bd9ba6123c647249616',
  uuid: '2902',
  name: 'Client Characteristic Configuration',
  type:
   'org.bluetooth.descriptor.gatt.client_characteristic_configuration' }

我不确定如何解释传递回的数据以进一步调试此问题。

Answer 1

您的数据是ATT响应。 1：错误响应的操作码 8：失败的请求的操作码（使用CCCD uuid的按类型读取请求） 54 00：从句柄搜索 10：错误代码“找不到属性”

所以我猜想该特性缺少客户端特性配置描述符。

高贵的BLE模块-feature.subscribe（）遇到错误

1 个答案: