How can I send data to peripheral from central when my nRF52832 is central then iPhone is peripheral

[Jacky Fu]

Hi everyone

I setting my nRF52832 is central and iPhone(iOS 12.3.2) is peripheral and using "ble_app_uart_c(SDK15.3.0  s132 v6.1.1)" sample program. I print the debug message from central, can see the message "<info> app: Connected to device with Nordic UART Service." But when I send data to peripheral from central, iPhone did not receive any information.

Here is my debug message:

<debug> ble_scan: Added filter on UUID 1

<info> app: BLE UART central example started.

<debug> ble_scan: Scanning

<debug> ble_scan: Connecting

<debug> ble_scan: Connection status: 0

<info> app: Connecting to target BD396002CC50

<debug> nrf_ble_gatt: Requesting to update ATT MTU to 247 bytes on connection 0x0.

<debug> nrf_ble_gatt: Updating data length to 251 on connection 0x0.

<debug> ble_db_disc: Starting discovery of service with UUID 0x1 on connection handle 0x0.

<debug> nrf_ble_gatt: Data length updated to 251 on connection 0x0.

<debug> nrf_ble_gatt: max_rx_octets: 251

<debug> nrf_ble_gatt: max_tx_octets: 251

<debug> nrf_ble_gatt: max_rx_time: 2120

<debug> nrf_ble_gatt: max_tx_time: 2120

<debug> ble_db_disc: Starting discovery of service with UUID 0x1 on connection handle 0x0.

<debug> nrf_ble_gatt: ATT MTU updated to 247 bytes on connection 0x0 (response).

<info> app: ATT MTU exchange completed.

<info> app: Ble NUS max data length set to 0xF4(244)

<debug> ble_db_disc: Found service UUID 0x1.

<debug> ble_db_disc: Discovery of service with UUID 0x1 completed with success on connection handle 0x0.

<info> ble_nus_c: ! nus_c_evt.handles.nus_rx_handle 44 !

<info> ble_nus_c: ! nus_c_evt.handles.nus_tx_handle 48 !

<info> ble_nus_c: ! nus_c_evt.handles.nus_tx_cccd_handle 4A !

<info> app: Discovery complete.

<info> app: Connected to device with Nordic UART Service.

Thanks everyone

[awneil]

So what code have you got running on the iPhone to implement NUS on the phone?

[Jacky Fu]

Hi awneil

iPhone code for NUS:

extension BluetoothManager: CBPeripheralManagerDelegate{
    
    func peripheralManagerDidUpdateState(_ peripheral: CBPeripheralManager) {
        switch peripheral.state {
        case .unknown:
            print("unknown")
        case .resetting:
            print("resetting")
        case .unsupported:
            print("unsupported")
        case .unauthorized:
            print("unauthorized")
        case .poweredOff:
            print("poweredOff")
        case .poweredOn:
            print("poweredOn")
            startAdvertisting()
        }
    }
    
    func startAdvertisting(){
        if let peripheralManager = self.peripheralManager{
            peripheralManager.stopAdvertising()
            peripheralManager.removeAllServices()
            if peripheralManager.state == .poweredOn{
                setupServiceAndCharacteristics()
            }
        }
    }
    
    func stopAdvertising(){
        self.peripheralManager?.stopAdvertising()
    }
    
    func writeDataToCentral(){
        let data = "helloWorld".data(using: .utf8)
        self.peripheralManager?.updateValue(data!, for: characteristic!, onSubscribedCentrals: nil)
    }
    
    

    func peripheralManager(_ peripheral: CBPeripheralManager, didReceiveRead request: CBATTRequest) {
        request.value = ?elloWorld??data(using: .utf8)
        peripheral.respond(to: request, withResult: .success)
        
        if let delegate = delegate{
            delegate.readCharacteristic()
        }
    }
    
    private func setupServiceAndCharacteristics() {
        let serviceID = CBUUID(string: Service_UUID)
        let service = CBMutableService(type: serviceID, primary: true)
        let characteristicID = CBUUID(string: Characteristic_UUID)
        let characteristicID2 = CBUUID(string: Characteristic_UUID2)
        let characteristic = CBMutableCharacteristic(type: characteristicID, properties: [.read, .write, .notify], value: nil, permissions: [.readable, .writeable])
        let characteristic2 = CBMutableCharacteristic(type: characteristicID2, properties: [.read, .write, .notify], value: nil, permissions: [.readable, .writeable, .readEncryptionRequired, .writeEncryptionRequired])
        service.characteristics = [characteristic, characteristic2]
        self.peripheralManager?.add(service)
    }
    
    func peripheralManager(_ peripheral: CBPeripheralManager, didReceiveWrite requests: [CBATTRequest]) {
        for request in requests{
            let text = String.init(data: request.value!, encoding: String.Encoding.utf8)
            if let text = text, let delegate = self.delegate{
                UserDefaults.standard.set(text, forKey: "text")
                delegate.receiveCentralData(text: text)
            }
        }

    }
    
    func peripheralManager(_ peripheral: CBPeripheralManager, didAdd service: CBService, error: Error?) {
        if let err = error{
            print("err = \(err)")
            return
        }
        print("add service success")
        self.peripheralManager?.startAdvertising([CBAdvertisementDataServiceUUIDsKey : [CBUUID.init(string: Service_UUID)], CBAdvertisementDataLocalNameKey: "55688"])
    }
    
    func peripheralManagerDidStartAdvertising(_ peripheral: CBPeripheralManager, error: Error?) {
        if let err = error{
            print("err = \(err)")
            return
        }
    }
}

  

Service_UUID = 6E400001-B5A3-F393-E0A9-E50E24DCCA9E

Create two Characteristics RX(Characteristic_UUID) and TX(Characteristic_UUID2), have set up "read", "write", "notify"

Characteristic_UUID =  6E400002-B5A3-F393-E0A9-E50E24DCCA9E

Characteristic_UUID2 =  6E400003-B5A3-F393-E0A9-E50E24DCCA9E

Thank you

[awneil]

So what debugging have you done on the iPhone end to see what's happening?

[Jacky Fu]

Hi awneil

I am trying to debug from iPhone

Thank you