ios - CoreBluetooth 无法读取固件修订字符串

Question

我正在尝试检索外围设备的固件版本字符串。

当通过“LightBlue”应用程序询问我的外围设备时，我能够查看设备信息，其中包括:

• 制造商名称字符串
• 固件版本字符串

但是，在我的代码中，我无法发现固件修订字符串的特征。我尝试了以下 UUID:

• 2A26
• 0x2A26
• 2a26
• 0x2a26

如何检索固件修订字符串？

Answer 1

首先需要发现相关的CBService。在这种情况下，它是设备信息服务。

首先在类/结构中的某处定义设备信息服务的 CBUUID 和固件修订字符串

let deviceInformationServiceUUID = CBUUID(string: "180a")
let firmwareRevisionStringCharacteristicUUID = CBUUID(string: "2a26")

然后在你的 CBCentralManagerDelegate 中:

// 1. Discover the services we care about upon initial connection
func centralManager(_ central: CBCentralManager, didConnect peripheral: CBPeripheral) {
    peripheral.discoverServices([deviceInformationServiceUUID])
}

然后在CBPeripheralDelegate中:

// 2. Discover the characteristics of the services we care about
func peripheral(_ peripheral: CBPeripheral, didDiscoverServices error: Error?) {
    guard error == nil else {
        print("Failed to discover services, error: \(error?.localizedDescription ?? "failed to obtain error description")")
        return
    }
    if let services = peripheral.services {
        services.forEach { peripheral.discoverCharacteristics(nil, for: $0) }
    }
}

// 3. Interrogate the characteristics and single out the firmware revision string characteristic, and read its value
func peripheral(_ peripheral: CBPeripheral, didDiscoverCharacteristicsFor service: CBService, error: Error?) {
    guard error == nil else {
        print("Failed to discover characteristics for service \(service.uuid), error: \(error?.localizedDescription ?? "no error description")")
        return
    }
    guard let discoveredCharacteristics = service.characteristics else {
        print("peripheralDidDiscoverCharacteristics called for empty characteristics for service \(service.uuid)")
        return
    }
    if service.uuid == deviceInformationServiceUUID {
        for characteristic in discoveredCharacteristics {
            if characteristic.uuid == firmwareRevisionStringCharacteristicUUID {
                print("Reading FW revision string for peripheral...")
                peripheral.readValue(for: characteristic)
                break
            }
        }
    }
}

// 4. Wait for value to be read and print it out
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
    guard let data = characteristic.value else {
        print("Unable to obtain notification/indication data from CBPeripheral")
        return
    }
    if characteristic.uuid == firmwareRevisionStringCharacteristicUUID,
        let firmwareRevisionString = String(data: data, encoding: .utf8) {
            logger.log(message: "FW revision string read as \(firmwareRevisionString)!")
    }
}