Connect BLE via NFC

[ycp]

Hi,all

     I need to connect BLE via NFC,but I do not know which example should i use to start。and i am a new field of NFC ,is there some document about NFC?thank you a lot !!

nRF5_SDK_17.1.0_ddde560

[Sigurd]

Hi!

We provide several examples in nRF5 SDK v17.1.0 that demonstrate the use of NFC for BLE pairing:

1. Writable NDEF Message Example: This example shows how to use the NFC tag to expose a writable NDEF message.
2. Experimental: BLE Pairing Using NFC - Peripheral Reference Example and Experimental: BLE Pairing Using NFC - Central Reference Example: 
3. Experimental: Heart Rate Application with BLE Pairing Using NFC Pairing Library: 
4. Experimental: HID Keyboard Application with BLE pairing using NFC: 
5. Experimental: BLE Heart Rate Collector Example with NFC Pairing: 

For detailed information about NFC and the available libraries and modules, you can refer to the NFC library and modules.

PS: If this is a new project, I strongly recommend using nRF Connect SDK instead: https://www.nordicsemi.com/Products/Development-software/nRF-Connect-SDK

Here I would recommend this sample to start with: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/samples/bluetooth/peripheral_nfc_pairing/README.html

[ycp]

thank you for you nice answer, i used this sample: nRF5_SDK_17.1.0_ddde560\examples\ble_peripheral\experimental\ble_app_hrs_nfc_pairing\pca10040.

Q1: it seems can bond between nrf52832 and smart phone ,but if i turn off the board,and turn on the board again ,it can not atuo conneted to the smart phone,is some config should i do? or the APP on smart phone should config something?

Q2:is there any function to test the antenna performance,output some value ,like RSSI? Aim to optimize the antenna  for a better sensing distance

thank you a lot!!

[Sigurd]

ycp said:

Q1: it seems can bond between nrf52832 and smart phone ,but if i turn off the board,and turn on the board again ,it can not atuo conneted to the smart phone,is some config should i do? or the APP on smart phone should config something?

If you have your own android app, then you have the autoConnect parameter in connectGatt() you can set to true

ycp said:

Q2:is there any function to test the antenna performance,output some value ,like RSSI? Aim to optimize the antenna  for a better sensing distance

It's already tuned on the DK. For custom nRF52 boards, see this white paper for NFC antenna tuning. https://infocenter.nordicsemi.com/topic/nwp_026/WP/nwp_026/nWP_026_intro.html

[ycp]

Thank you,it is vary useful !,

I have Q3:if the board boned with a phone ,next time this phone put on the board again ,will it pair again? i wish it can  just connect ,do not pair ,what i should do?

i read the code below,it seems will generate new Authentication OOB Key again.thank you a lot!

/**
 * @brief Function for handling NFC events.
 *
 * @details Starts advertising and generates new OOB keys on the NFC_T2T_EVENT_FIELD_ON event.
 *
 * @param[in] p_context    Context for callback execution, not used in this callback implementation.
 * @param[in] event        Event generated by hal NFC lib.
 * @param[in] p_data       Received/transmitted data or NULL, not used in this callback implementation.
 * @param[in] data_length  Size of the received/transmitted packet, not used in this callback implementation.
 */
static void nfc_callback(void            * p_context,
                         nfc_t2t_event_t   event,
                         uint8_t const   * p_data,
                         size_t            data_length)
{
    UNUSED_PARAMETER(p_context);
    UNUSED_PARAMETER(p_data);
    UNUSED_PARAMETER(data_length);

    ret_code_t         err_code = NRF_SUCCESS;
    nfc_pairing_mode_t pairing_mode;

    switch (event)
    {
        case NFC_T2T_EVENT_FIELD_ON:
            NRF_LOG_DEBUG("NFC_EVENT_FIELD_ON");

            pairing_mode = nfc_ble_pair_mode_get();

            if ((pairing_mode == NFC_PAIRING_MODE_OOB) ||
                (pairing_mode == NFC_PAIRING_MODE_GENERIC_OOB))
            {
                // Generate Authentication OOB Key and update NDEF message content.
                uint8_t length = random_vector_generate(m_oob_auth_key.tk, BLE_GAP_SEC_KEY_LEN);
                random_vector_log(length);
                err_code = nfc_tk_group_modifier_update(&m_oob_auth_key);
                APP_ERROR_CHECK(err_code);
            }

            // Start advertising when NFC field is sensed and there is a place for another connection.
            if (m_connections < NRF_SDH_BLE_PERIPHERAL_LINK_COUNT)
            {
                err_code = ble_advertising_start(m_p_advertising, BLE_ADV_MODE_FAST);
                if (err_code != NRF_ERROR_INVALID_STATE)
                {
                    APP_ERROR_CHECK(err_code);
                }
            }

            break;

        case NFC_T2T_EVENT_FIELD_OFF:
            NRF_LOG_DEBUG("NFC_EVENT_FIELD_OFF");
            break;

        default:
            break;
    }
}

[ycp]

Q4:can I use S332 softdevice to run NFC ? Because the project  need ANT+ feature too!

[Sigurd]

Hi!

ycp said:

I have Q3:if the board boned with a phone ,next time this phone put on the board again ,will it pair again? i wish it can  just connect ,do not pair ,what i should do?

You only need to bond once. If you turn off the board, and on again, and connect with the phone, you don't need to pair/bond again.

ycp said:

can I use S332 softdevice to run NFC ?

Yes, that should work.

[ycp]

thank you very much! i got it!