RE: rssi vial serial communication

Sigurd — Tue, 20 Feb 2018 09:46:30 GMT

Hi,

I suggest basing this on the ble_app_uart (slave) and ble_app_uart_c (master) examples in the SDK, and use two nRF52832 DK for the demo. I recommened using the latest SDK version 14.2 for this.

Changes that need to be done one ble_app_uart(slave):

In function ble_evt_handler() under the event BLE_GAP_EVT_CONNECTED, start the rssi reporting when the connection is established, with sd_ble_gap_rssi_start(m_conn_handle,1,1);

Define, and implement the rssi app timer used to print the RSSI value:

APP_TIMER_DEF(m_rssi_timer_id);                         
#define RSSI_MEAS_INTERVAL         APP_TIMER_TICKS(200)                

static void rssi_timeout_handler(void * p_context)
{
    UNUSED_PARAMETER(p_context);
    int8_t p_rssi;
    if(m_conn_handle != BLE_CONN_HANDLE_INVALID)
    {
       if(sd_ble_gap_rssi_get(m_conn_handle,&p_rssi) == NRF_SUCCESS)
        {

        printf("RSSI = %d\r\n",p_rssi);

        }
    }

}

In main(), make sure that you create and start the rssi app timer, with app_timer_create() and app_timer_start(). The main() should then look like this:

int main(void)
{
    uint32_t err_code;
    bool     erase_bonds;

    // Initialize.
    err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
    err_code = app_timer_create(&m_rssi_timer_id,
                                APP_TIMER_MODE_REPEATED,
                                rssi_timeout_handler);
    err_code = app_timer_start(m_rssi_timer_id, RSSI_MEAS_INTERVAL, NULL);
    APP_ERROR_CHECK(err_code);

    uart_init();
    log_init();

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

    printf("\r\nUART Start!\r\n");
    NRF_LOG_INFO("UART Start!");
    err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);

    // Enter main loop.
    for (;;)
    {
        UNUSED_RETURN_VALUE(NRF_LOG_PROCESS());
        power_manage();
    }
}

Use the same method with ble_app_uart_c.

The RSSI values will be printed over UART. If you have connected the DKs to the PC, open a terminal, such as Termite to view the RSSI values. I have attached the main.c files I used when testing this for both slave and master. I used SDK 14.2 for this.

devzone.nordicsemi.com/.../main_5F00_slave.c

devzone.nordicsemi.com/.../main_5F00_central.c