How can I reduce time between sd_ble_gatts_hvx() to BLE_GATT_EVT_HVN_TX_COMPLETE event

[KHH]

When I send hid data using below function. (length of data is just 5)

        err_code = ble_hids_inp_rep_send(p_hids,

            index,

            len,

            pattern,

            m_conn_handle);

 

And I measured the time between sd_ble_gatts_hvx() to BLE_GATT_EVT_HVN_TX_COMPLETE event: using gpio toggle.

It takes 50ms....

I want to reduce this time.. because of this time there is delay.

How can I reduce??

Ps. I am using freertos.

[Sigurd]

Hi,

Maybe you have 50ms connection interval for the BLE link.

You should try to reduce the connection interval.

[KHH]

Thank you for your answer~! How can I change that interval time???

my gatt define is below 

#define MIN_CONN_INTERVAL                   MSEC_TO_UNITS(7.5, UNIT_1_25_MS)           /**< Minimum connection interval (7.5 ms) */

#define MAX_CONN_INTERVAL                   MSEC_TO_UNITS(30, UNIT_1_25_MS)            /**< Maximum connection interval (30 ms). */

#define SLAVE_LATENCY                       6                                          /**< Slave latency. */

#define CONN_SUP_TIMEOUT                    MSEC_TO_UNITS(430, UNIT_10_MS)             /**< Connection supervisory timeout (430 ms). */

and my init function

static void gap_params_init(void)

{

    ret_code_t              err_code;

    ble_gap_conn_params_t   gap_conn_params;

    ble_gap_conn_sec_mode_t sec_mode;

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);

    err_code = sd_ble_gap_device_name_set(&sec_mode,

                                          (const uint8_t *)DEVICE_NAME,

                                          strlen(DEVICE_NAME));

    APP_ERROR_CHECK(err_code);

    err_code = sd_ble_gap_appearance_set(BLE_APPEARANCE_HID_KEYBOARD);

    APP_ERROR_CHECK(err_code);

    memset(&gap_conn_params, 0, sizeof(gap_conn_params));

    gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;

    gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;

    gap_conn_params.slave_latency     = SLAVE_LATENCY;

    gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;

    err_code = sd_ble_gap_ppcp_set(&gap_conn_params);

    APP_ERROR_CHECK(err_code);

}

[Sigurd]

Your defines looks correct.

I recommend checking what parameters the link is actually using, by using the nRF Sniffer to take a on-air sniffer trace. https://www.nordicsemi.com/Software-and-tools/Development-Tools/nRF-Sniffer-for-Bluetooth-LE