nRF52 BLE 개발하기 - ble_app_buttonless_dfu

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지난 글에서 DFU 기능을 이용해 블루투스로 펌웨어 업데이트를 진행하는 방법에 대해서 알아보았다.

다시 DFU 기능을 이용하기 위해서는 부트로더로 다시 진입해야 한다.

부트로더에 진입하는 방법은 크게 2가지 방식이 있는데 버튼을 눌러 부트로더에 진입하는 것과 DFU 서비스를 통해 진입하는 방식이다.

그 방법 중 가장 많이 이용되고 있는 DFU 서비스를 이용한 Buttonless DFU에 대해서 알아보고자 한다.

먼저 \examples\ble_peripheral\ble_app_buttonless_dfu\pca10040\s132\ses 폴더에서 프로젝트를 실행해보자.

#define DEVICE_NAME                     "Nordic_Buttonless"                         /**< Name of device. Will be included in the advertising data. */
#define MANUFACTURER_NAME               "NordicSemiconductor"                       /**< Manufacturer. Will be passed to Device Information Service. */
#define APP_ADV_INTERVAL                300                                         /**< The advertising interval (in units of 0.625 ms. This value corresponds to 187.5 ms). */
#define APP_ADV_DURATION                18000                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */
#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)            /**< Minimum acceptable connection interval (0.1 seconds). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)            /**< Maximum acceptable connection interval (0.2 second). */
#define SLAVE_LATENCY                   0                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds). */

#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)                       /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000)                      /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define SEC_PARAM_BOND                  1                                           /**< Perform bonding. */
#define SEC_PARAM_MITM                  0                                           /**< Man In The Middle protection not required. */
#define SEC_PARAM_LESC                  0                                           /**< LE Secure Connections not enabled. */
#define SEC_PARAM_KEYPRESS              0                                           /**< Keypress notifications not enabled. */
#define SEC_PARAM_IO_CAPABILITIES       BLE_GAP_IO_CAPS_NONE                        /**< No I/O capabilities. */
#define SEC_PARAM_OOB                   0                                           /**< Out Of Band data not available. */
#define SEC_PARAM_MIN_KEY_SIZE          7                                           /**< Minimum encryption key size. */
#define SEC_PARAM_MAX_KEY_SIZE          16                                          /**< Maximum encryption key size. */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */


NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);                                                             /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);                                                 /**< Advertising module instance. */

static uint16_t m_conn_handle = BLE_CONN_HANDLE_INVALID;                            /**< Handle of the current connection. */
static void advertising_start(bool erase_bonds);                                    /**< Forward declaration of advertising start function */

// YOUR_JOB: Use UUIDs for service(s) used in your application.
static ble_uuid_t m_adv_uuids[] = {{BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE}};

/**@brief Function for application main entry.
 */
int main(void)
{
    bool       erase_bonds;
    ret_code_t err_code;

    log_init();

    // Initialize the async SVCI interface to bootloader before any interrupts are enabled.
    err_code = ble_dfu_buttonless_async_svci_init();
    APP_ERROR_CHECK(err_code);

    timers_init();
    power_management_init();
    buttons_leds_init(&erase_bonds);
    ble_stack_init();
    peer_manager_init();
    gap_params_init();
    gatt_init();
    advertising_init();
    services_init();
    conn_params_init();

    NRF_LOG_INFO("Buttonless DFU Application started.");

    // Start execution.
    application_timers_start();
    advertising_start(erase_bonds);

    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

ble_dfu_buttonless_async_svci_init 함수를 호출해 SVCI 인터페이스를 통해 부트로더를 호출할 수 있도록 설정한다.

peer_manager_init 함수를 호출해 블루투스 피어 매니저 기능을 사용할 수 있도록 설정한다.

services_init 함수에서 ble_dfu_buttonless_init 함수로 DFU 서비스를 등록해준다.

ble_dfu_evt_handler 함수로 DFU 서비스 이벤트 발생에 따른 동작을 정해줄 수 있다.

/**@brief Function for handling dfu events from the Buttonless Secure DFU service
 *
 * @param[in]   event   Event from the Buttonless Secure DFU service.
 */
static void ble_dfu_evt_handler(ble_dfu_buttonless_evt_type_t event)
{
    switch (event)
    {
        case BLE_DFU_EVT_BOOTLOADER_ENTER_PREPARE:
        {
            NRF_LOG_INFO("Device is preparing to enter bootloader mode.");

            // Prevent device from advertising on disconnect.
            ble_adv_modes_config_t config;
            advertising_config_get(&config);
            config.ble_adv_on_disconnect_disabled = true;
            ble_advertising_modes_config_set(&m_advertising, &config);

            // Disconnect all other bonded devices that currently are connected.
            // This is required to receive a service changed indication
            // on bootup after a successful (or aborted) Device Firmware Update.
            uint32_t conn_count = ble_conn_state_for_each_connected(disconnect, NULL);
            NRF_LOG_INFO("Disconnected %d links.", conn_count);
            break;
        }

        case BLE_DFU_EVT_BOOTLOADER_ENTER:
            // YOUR_JOB: Write app-specific unwritten data to FLASH, control finalization of this
            //           by delaying reset by reporting false in app_shutdown_handler
            NRF_LOG_INFO("Device will enter bootloader mode.");
            break;

        case BLE_DFU_EVT_BOOTLOADER_ENTER_FAILED:
            NRF_LOG_ERROR("Request to enter bootloader mode failed asynchroneously.");
            // YOUR_JOB: Take corrective measures to resolve the issue
            //           like calling APP_ERROR_CHECK to reset the device.
            break;

        case BLE_DFU_EVT_RESPONSE_SEND_ERROR:
            NRF_LOG_ERROR("Request to send a response to client failed.");
            // YOUR_JOB: Take corrective measures to resolve the issue
            //           like calling APP_ERROR_CHECK to reset the device.
            APP_ERROR_CHECK(false);
            break;

        default:
            NRF_LOG_ERROR("Unknown event from ble_dfu_buttonless.");
            break;
    }
}

/**@brief Function for initializing services that will be used by the application.
 */
static void services_init(void)
{
    uint32_t                  err_code;
    nrf_ble_qwr_init_t        qwr_init  = {0};
    ble_dfu_buttonless_init_t dfus_init = {0};

    // Initialize Queued Write Module.
    qwr_init.error_handler = nrf_qwr_error_handler;

    err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
    APP_ERROR_CHECK(err_code);

    dfus_init.evt_handler = ble_dfu_evt_handler;

    err_code = ble_dfu_buttonless_init(&dfus_init);
    APP_ERROR_CHECK(err_code);

    /* YOUR_JOB: Add code to initialize the services used by the application.
       uint32_t                           err_code;
       ble_xxs_init_t                     xxs_init;
       ble_yys_init_t                     yys_init;

       // Initialize XXX Service.
       memset(&xxs_init, 0, sizeof(xxs_init));

       xxs_init.evt_handler                = NULL;
       xxs_init.is_xxx_notify_supported    = true;
       xxs_init.ble_xx_initial_value.level = 100;

       err_code = ble_bas_init(&m_xxs, &xxs_init);
       APP_ERROR_CHECK(err_code);

       // Initialize YYY Service.
       memset(&yys_init, 0, sizeof(yys_init));
       yys_init.evt_handler                  = on_yys_evt;
       yys_init.ble_yy_initial_value.counter = 0;

       err_code = ble_yy_service_init(&yys_init, &yy_init);
       APP_ERROR_CHECK(err_code);
     */
}

uint32_t ble_dfu_buttonless_init(const ble_dfu_buttonless_init_t * p_dfu_init)
{
    uint32_t        err_code;
    ble_uuid_t      service_uuid;
    ble_uuid128_t   nordic_base_uuid = BLE_NORDIC_VENDOR_BASE_UUID;

    VERIFY_PARAM_NOT_NULL(p_dfu_init);

    // Initialize the service structure.
    m_dfu.conn_handle                  = BLE_CONN_HANDLE_INVALID;
    m_dfu.evt_handler                  = p_dfu_init->evt_handler;
    m_dfu.is_waiting_for_reset         = false;

    if (m_dfu.evt_handler == NULL)
    {
        m_dfu.evt_handler = dummy_evt_handler;
    }

    err_code = ble_dfu_buttonless_backend_init(&m_dfu);
    VERIFY_SUCCESS(err_code);

    BLE_UUID_BLE_ASSIGN(service_uuid, BLE_DFU_SERVICE_UUID);

    // Add the DFU service declaration.
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY,
                                        &service_uuid,
                                        &(m_dfu.service_handle));

    VERIFY_SUCCESS(err_code);

    // Add vendor specific base UUID to use with the Buttonless DFU characteristic.
    err_code = sd_ble_uuid_vs_add(&nordic_base_uuid, &m_dfu.uuid_type);
    VERIFY_SUCCESS(err_code);

    // Add the Buttonless DFU Characteristic (with bonds/without bonds).
    err_code = ble_dfu_buttonless_char_add(&m_dfu);
    VERIFY_SUCCESS(err_code);

    return NRF_SUCCESS;
}

이렇게 부트로더로 진입할 수 있는 블루투스 DFU 서비스 등록을 마치고 Advertising을 시작하면 끝난다.

이제 nRF52 DK에 다시 부트로더 펌웨어를 다운로드하고 이전 글과 마찬가지로 예제를 패키징하여 DFU를 통해 업로드하자.

펌웨어가 업로드된 상태에서 nRF Toolbox 애플리케이션 DFU 항목에서 Nordic_Buttonless을 연결하고 다시 펌웨어를 업로드해보자.

이제 DFU 서비스를 통해 언제든지 nRF52 DK를 부트로더에 진입시켜 블루투스를 통해 펌웨어를 업데이트할 수 있게 되었다.

앞으로

지금까지 부트로더 DFU 기능과 DFU 서비스를 통해 펌웨어를 업데이트하는 방법에 대해서 알아보았다.

다음 글에서는 다른 예제에 ble_app_buttonless_dfu 예제를 응용하는 방법에 대해서 알아보도록 하자.