BLE协议栈-GATTvsATT
通过BLE协议栈，设备可以使用GATT（通用属性）协议与其他BLE设备进行通信。GATT运行在ATT（属性）协议之上，定义了一组通用属性用于交换数据。ATT定义了两个基本数据类型：属性和属性值，并使用UUID（唯一标识符）来识别属性和属性值。下面给出包含代码的示例：
- GATT服务器示例：
const uint16_t CHAR1_UUID = 0x1111; const uint16_t CHAR2_UUID = 0x2222;
BLEService myService; BLECharacteristic char1(CHAR1_UUID, BLECharacteristic::PROPERTY_READ | BLECharacteristic::PROPERTY_NOTIFY); BLECharacteristic char2(CHAR2_UUID, BLECharacteristic::PROPERTY_WRITE);
void setup() { myService.addCharacteristic(char1); myService.addCharacteristic(char2); BLE.setLocalName("MyDevice"); BLE.setAdvertisedService(myService); BLE.addService(myService); char1.writeValue(0x00); }
void loop() { BLEDevice central = BLE.central(); if (central) { while (central.connected()) { if (char1.written()) { uint8_t value = char1.value(); // 处理 char1 写入的值 } if (char2.read()) { // 发送 char2 的值给中心设备 char2.notify(); } } } }
- GATT客户端示例：
const uint16_t CHAR1_UUID = 0x1111; const uint16_t CHAR2_UUID = 0x2222;
BLEClient bleClient;
void setup() { BLE.setLocalName("MyClient"); BLE.setAdvertisedServiceUuid(BLEUUID((uint16_t)0x180D)); }
void loop() { if (bleClient.connect()) { BLEService myService = bleClient.getService(BLEUUID((uint16_t)0x180D)); if (myService) { BLECharacteristic char1 = myService.getCharacteristic(BLEUUID(CHAR1_UUID)); BLECharacteristic char2 = myService.getCharacteristic(B