In my application I have a custom board with a single LED. While advertising the LED blinks at 1Hz and when connected the LED goes solid. However while testing with a proven Android application I notice that occasionally on disconnect the timer doesn't restart as desired but is instead delayed anywhere between 2 and 8 seconds. After that it begins blinking correctly. One thing to note is that I'm using the Internal RC which is temperature calibrated every 4 seconds. The following code will clarify the situation:
EDIT: I'm using SD 7.0.0 and SDK 6.0
Here you can see how I toggle the LED when connected/disconnected and call advertising_start when necessary.
case BLE_GAP_EVT_CONNECTED:
m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
// Stop the advertising LED timer
err_code = app_timer_stop(m_app_timer_id);
APP_ERROR_CHECK(err_code);
// Make LED go solid indicating a connection
nrf_gpio_pin_set(ADVERTISING_LED_PIN_NO);
break;
case BLE_GAP_EVT_DISCONNECTED:
m_conn_handle = BLE_CONN_HANDLE_INVALID;
nrf_gpio_pin_clear(ADVERTISING_LED_PIN_NO);
advertising_start();
break;
In advertising start I kick off the timer as shown below (it's already created).
static void advertising_start(void)
{
uint32_t err_code;
ble_gap_adv_params_t adv_params;
// Start advertising
memset(&adv_params, 0, sizeof(adv_params));
adv_params.type = BLE_GAP_ADV_TYPE_ADV_IND;
adv_params.p_peer_addr = NULL;
adv_params.fp = BLE_GAP_ADV_FP_ANY;
adv_params.interval = APP_ADV_INTERVAL;
adv_params.timeout = APP_ADV_TIMEOUT_IN_SECONDS;
err_code = sd_ble_gap_adv_start(&adv_params);
APP_ERROR_CHECK(err_code);
err_code = app_timer_start(m_app_timer_id, 32768/2, NULL);
APP_ERROR_CHECK(err_code);
}
